diff --git a/NEWS b/NEWS
index b83551f1..00f4fe47 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,75 @@
+Notmuch 0.38 (2023-09-12)
+=========================
+
+General
+-------
+
+Support relative lastmod queries (see notmuch-sexp-queries(7) and
+notmuch-search-terms(7) for details).
+
+Support indexing of designated attachments as text (see
+notmuch-config(1) for details).
+
+CLI
+---
+
+Add options --offset and --limit to notmuch-show(1).
+
+Emacs
+-----
+
+New commands notmuch-search-edit-search and notmuch-tree-edit-search.
+
+Introduce notmuch-tree-outline-mode.
+
+Some compatibility fixes for Emacs 29. At least one issue (hiding
+images) remains in 0.38.
+
+Support completion when piping to external command.
+
+Fix regression in updating tag display introduced by 0.37.
+
+Library
+-------
+
+Fix bug creating database when database.path is not set.
+
+Incremental performance improvements for message deletion.
+
+Catch Xapian exceptions when deleting messages.
+
+Sync removed message properties to the database.
+
+Replace use of thread-unsafe Query::MatchAll in the infix query
+parser.
+
+Notmuch-Mutt
+------------
+
+Be more careful when clearing the results directory.
+
+Ruby
+----
+
+Use `database_open_with_config`, and provide compatible path search
+semantics.
+
+Bugfix for query.get_sort
+
+Test Suite
+----------
+
+Support testing installed version of notmuch.
+
+Adapt to some breaking changes in glib handling of init files.
+
+Replace OpenPGP key used in test suite.
+
+Performance Tests
+-----------------
+
+Update signatures for performance test corpus.
+
 Notmuch 0.37 (2022-08-21)
 =========================
 
diff --git a/bindings/Makefile.local b/bindings/Makefile.local
index 7b10af08..9875123a 100644
--- a/bindings/Makefile.local
+++ b/bindings/Makefile.local
@@ -34,3 +34,7 @@ CLEAN += $(patsubst %,$(dir)/ruby/%, \
 CLEAN += bindings/ruby/.vendorarchdir.time $(dir)/ruby.stamp
 
 CLEAN += bindings/python-cffi/build $(dir)/python-cffi.stamp
+CLEAN += bindings/python-cffi/__pycache__
+
+DISTCLEAN += bindings/python-cffi/_notmuch_config.py \
+	bindings/python-cffi/notmuch2.egg-info
diff --git a/bindings/python/notmuch/compat.py b/bindings/python/notmuch/compat.py
index c931329e..4a94e05c 100644
--- a/bindings/python/notmuch/compat.py
+++ b/bindings/python/notmuch/compat.py
@@ -47,7 +47,10 @@ if sys.version_info[0] == 2:
 
         return value
 else:
-    from configparser import SafeConfigParser
+    from configparser import ConfigParser as SafeConfigParser
+
+    if not hasattr(SafeConfigParser, 'readfp'):   # py >= 3.12
+        SafeConfigParser.readfp = SafeConfigParser.read_file
 
     class Python3StringMixIn(object):
         def __str__(self):
diff --git a/bindings/python/notmuch/version.py b/bindings/python/notmuch/version.py
index 943f335c..c847a1a3 100644
--- a/bindings/python/notmuch/version.py
+++ b/bindings/python/notmuch/version.py
@@ -1,3 +1,3 @@
 # this file should be kept in sync with ../../../version
-__VERSION__ = '0.37'
+__VERSION__ = '0.38'
 SOVERSION = '5'
diff --git a/bindings/ruby/database.c b/bindings/ruby/database.c
index 9c3dbd96..ed224ef7 100644
--- a/bindings/ruby/database.c
+++ b/bindings/ruby/database.c
@@ -58,40 +58,56 @@ notmuch_rb_database_initialize (int argc, VALUE *argv, VALUE self)
     notmuch_database_t *database;
     notmuch_status_t ret;
 
-    /* Check arguments */
-    rb_scan_args (argc, argv, "11", &pathv, &hashv);
+    path = NULL;
+    create = 0;
+    mode = NOTMUCH_DATABASE_MODE_READ_ONLY;
 
-    SafeStringValue (pathv);
-    path = RSTRING_PTR (pathv);
+    /* Check arguments */
+    rb_scan_args (argc, argv, "02", &pathv, &hashv);
+
+    if (!NIL_P (pathv)) {
+	SafeStringValue (pathv);
+	path = RSTRING_PTR (pathv);
+    }
 
     if (!NIL_P (hashv)) {
-	Check_Type (hashv, T_HASH);
-	create = RTEST (rb_hash_aref (hashv, ID2SYM (ID_db_create)));
-	modev = rb_hash_aref (hashv, ID2SYM (ID_db_mode));
-	if (NIL_P (modev))
-	    mode = NOTMUCH_DATABASE_MODE_READ_ONLY;
-	else if (!FIXNUM_P (modev))
-	    rb_raise (rb_eTypeError, ":mode isn't a Fixnum");
-	else {
-	    mode = FIX2INT (modev);
-	    switch (mode) {
-	    case NOTMUCH_DATABASE_MODE_READ_ONLY:
-	    case NOTMUCH_DATABASE_MODE_READ_WRITE:
-		break;
-	    default:
-		rb_raise ( rb_eTypeError, "Invalid mode");
+	VALUE rmode, rcreate;
+	VALUE kwargs[2];
+	static ID keyword_ids[2];
+
+	if (!keyword_ids[0]) {
+	    keyword_ids[0] = rb_intern_const ("mode");
+	    keyword_ids[1] = rb_intern_const ("create");
+	}
+
+	rb_get_kwargs (hashv, keyword_ids, 0, 2, kwargs);
+
+	rmode = kwargs[0];
+	rcreate = kwargs[1];
+
+	if (rmode != Qundef) {
+	    if (!FIXNUM_P (rmode))
+		rb_raise (rb_eTypeError, ":mode isn't a Fixnum");
+	    else {
+		mode = FIX2INT (rmode);
+		switch (mode) {
+		case NOTMUCH_DATABASE_MODE_READ_ONLY:
+		case NOTMUCH_DATABASE_MODE_READ_WRITE:
+		    break;
+		default:
+		    rb_raise ( rb_eTypeError, "Invalid mode");
+		}
 	    }
 	}
-    } else {
-	create = 0;
-	mode = NOTMUCH_DATABASE_MODE_READ_ONLY;
+	if (rcreate != Qundef)
+	    create = RTEST (rcreate);
     }
 
     rb_check_typeddata (self, &notmuch_rb_database_type);
     if (create)
 	ret = notmuch_database_create (path, &database);
     else
-	ret = notmuch_database_open (path, mode, &database);
+	ret = notmuch_database_open_with_config (path, mode, NULL, NULL, &database, NULL);
     notmuch_rb_status_raise (ret);
 
     DATA_PTR (self) = notmuch_rb_object_create (database, "notmuch_rb_database");
@@ -408,7 +424,7 @@ notmuch_rb_database_get_all_tags (VALUE self)
 
 	rb_raise (notmuch_rb_eBaseError, "%s", msg);
     }
-    return Data_Wrap_Notmuch_Object (notmuch_rb_cTags, &notmuch_rb_tags_type, tags);
+    return notmuch_rb_tags_get (tags);
 }
 
 /*
diff --git a/bindings/ruby/defs.h b/bindings/ruby/defs.h
index e2541e8f..a2cb38c8 100644
--- a/bindings/ruby/defs.h
+++ b/bindings/ruby/defs.h
@@ -33,7 +33,6 @@ extern VALUE notmuch_rb_cThreads;
 extern VALUE notmuch_rb_cThread;
 extern VALUE notmuch_rb_cMessages;
 extern VALUE notmuch_rb_cMessage;
-extern VALUE notmuch_rb_cTags;
 
 extern VALUE notmuch_rb_eBaseError;
 extern VALUE notmuch_rb_eDatabaseError;
@@ -48,8 +47,6 @@ extern VALUE notmuch_rb_eUnbalancedFreezeThawError;
 extern VALUE notmuch_rb_eUnbalancedAtomicError;
 
 extern ID ID_call;
-extern ID ID_db_create;
-extern ID ID_db_mode;
 
 /* RSTRING_PTR() is new in ruby-1.9 */
 #if !defined(RSTRING_PTR)
@@ -59,7 +56,6 @@ extern ID ID_db_mode;
 extern const rb_data_type_t notmuch_rb_object_type;
 extern const rb_data_type_t notmuch_rb_database_type;
 extern const rb_data_type_t notmuch_rb_directory_type;
-extern const rb_data_type_t notmuch_rb_filenames_type;
 extern const rb_data_type_t notmuch_rb_query_type;
 extern const rb_data_type_t notmuch_rb_threads_type;
 extern const rb_data_type_t notmuch_rb_thread_type;
@@ -92,9 +88,6 @@ extern const rb_data_type_t notmuch_rb_tags_type;
 #define Data_Get_Notmuch_Directory(obj, ptr) \
     Data_Get_Notmuch_Object ((obj), &notmuch_rb_directory_type, (ptr))
 
-#define Data_Get_Notmuch_FileNames(obj, ptr) \
-    Data_Get_Notmuch_Object ((obj), &notmuch_rb_filenames_type, (ptr))
-
 #define Data_Get_Notmuch_Query(obj, ptr) \
     Data_Get_Notmuch_Object ((obj), &notmuch_rb_query_type, (ptr))
 
@@ -226,10 +219,7 @@ notmuch_rb_directory_get_child_directories (VALUE self);
 
 /* filenames.c */
 VALUE
-notmuch_rb_filenames_destroy (VALUE self);
-
-VALUE
-notmuch_rb_filenames_each (VALUE self);
+notmuch_rb_filenames_get (notmuch_filenames_t *fnames);
 
 /* query.c */
 VALUE
@@ -370,10 +360,7 @@ notmuch_rb_message_thaw (VALUE self);
 
 /* tags.c */
 VALUE
-notmuch_rb_tags_destroy (VALUE self);
-
-VALUE
-notmuch_rb_tags_each (VALUE self);
+notmuch_rb_tags_get (notmuch_tags_t *tags);
 
 /* init.c */
 void
diff --git a/bindings/ruby/directory.c b/bindings/ruby/directory.c
index 910f0a99..f267d82f 100644
--- a/bindings/ruby/directory.c
+++ b/bindings/ruby/directory.c
@@ -87,7 +87,7 @@ notmuch_rb_directory_get_child_files (VALUE self)
 
     fnames = notmuch_directory_get_child_files (dir);
 
-    return Data_Wrap_Notmuch_Object (notmuch_rb_cFileNames, &notmuch_rb_filenames_type, fnames);
+    return notmuch_rb_filenames_get (fnames);
 }
 
 /*
@@ -106,5 +106,5 @@ notmuch_rb_directory_get_child_directories (VALUE self)
 
     fnames = notmuch_directory_get_child_directories (dir);
 
-    return Data_Wrap_Notmuch_Object (notmuch_rb_cFileNames, &notmuch_rb_filenames_type, fnames);
+    return notmuch_rb_filenames_get (fnames);
 }
diff --git a/bindings/ruby/filenames.c b/bindings/ruby/filenames.c
index 0dec1952..60c3fb8b 100644
--- a/bindings/ruby/filenames.c
+++ b/bindings/ruby/filenames.c
@@ -1,53 +1,11 @@
-/* The Ruby interface to the notmuch mail library
- *
- * Copyright © 2010 Ali Polatel
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see https://www.gnu.org/licenses/ .
- *
- * Author: Ali Polatel <alip@exherbo.org>
- */
-
 #include "defs.h"
 
-/*
- * call-seq: FILENAMES.destroy! => nil
- *
- * Destroys the filenames, freeing all resources allocated for it.
- */
 VALUE
-notmuch_rb_filenames_destroy (VALUE self)
+notmuch_rb_filenames_get (notmuch_filenames_t *fnames)
 {
-    notmuch_rb_object_destroy (self, &notmuch_rb_filenames_type);
-
-    return Qnil;
-}
-
-/*
- * call-seq: FILENAMES.each {|item| block } => FILENAMES
- *
- * Calls +block+ once for each element in +self+, passing that element as a
- * parameter.
- */
-VALUE
-notmuch_rb_filenames_each (VALUE self)
-{
-    notmuch_filenames_t *fnames;
-
-    Data_Get_Notmuch_FileNames (self, fnames);
+    VALUE rb_array = rb_ary_new ();
 
     for (; notmuch_filenames_valid (fnames); notmuch_filenames_move_to_next (fnames))
-	rb_yield (rb_str_new2 (notmuch_filenames_get (fnames)));
-
-    return self;
+	rb_ary_push (rb_array, rb_str_new2 (notmuch_filenames_get (fnames)));
+    return rb_array;
 }
diff --git a/bindings/ruby/init.c b/bindings/ruby/init.c
index cd9f04cd..2d1994af 100644
--- a/bindings/ruby/init.c
+++ b/bindings/ruby/init.c
@@ -22,13 +22,11 @@
 
 VALUE notmuch_rb_cDatabase;
 VALUE notmuch_rb_cDirectory;
-VALUE notmuch_rb_cFileNames;
 VALUE notmuch_rb_cQuery;
 VALUE notmuch_rb_cThreads;
 VALUE notmuch_rb_cThread;
 VALUE notmuch_rb_cMessages;
 VALUE notmuch_rb_cMessage;
-VALUE notmuch_rb_cTags;
 
 VALUE notmuch_rb_eBaseError;
 VALUE notmuch_rb_eDatabaseError;
@@ -43,8 +41,6 @@ VALUE notmuch_rb_eUnbalancedFreezeThawError;
 VALUE notmuch_rb_eUnbalancedAtomicError;
 
 ID ID_call;
-ID ID_db_create;
-ID ID_db_mode;
 
 const rb_data_type_t notmuch_rb_object_type = {
     .wrap_struct_name = "notmuch_object",
@@ -65,13 +61,11 @@ const rb_data_type_t notmuch_rb_object_type = {
 
 define_type (database);
 define_type (directory);
-define_type (filenames);
 define_type (query);
 define_type (threads);
 define_type (thread);
 define_type (messages);
 define_type (message);
-define_type (tags);
 
 /*
  * Document-module: Notmuch
@@ -86,13 +80,11 @@ define_type (tags);
  * the user:
  *
  * - Notmuch::Database
- * - Notmuch::FileNames
  * - Notmuch::Query
  * - Notmuch::Threads
  * - Notmuch::Messages
  * - Notmuch::Thread
  * - Notmuch::Message
- * - Notmuch::Tags
  */
 
 void
@@ -101,8 +93,6 @@ Init_notmuch (void)
     VALUE mod;
 
     ID_call = rb_intern ("call");
-    ID_db_create = rb_intern ("create");
-    ID_db_mode = rb_intern ("mode");
 
     mod = rb_define_module ("Notmuch");
 
@@ -297,17 +287,6 @@ Init_notmuch (void)
     rb_define_method (notmuch_rb_cDirectory, "child_files", notmuch_rb_directory_get_child_files, 0); /* in directory.c */
     rb_define_method (notmuch_rb_cDirectory, "child_directories", notmuch_rb_directory_get_child_directories, 0); /* in directory.c */
 
-    /*
-     * Document-class: Notmuch::FileNames
-     *
-     * Notmuch file names
-     */
-    notmuch_rb_cFileNames = rb_define_class_under (mod, "FileNames", rb_cObject);
-    rb_undef_method (notmuch_rb_cFileNames, "initialize");
-    rb_define_method (notmuch_rb_cFileNames, "destroy!", notmuch_rb_filenames_destroy, 0); /* in filenames.c */
-    rb_define_method (notmuch_rb_cFileNames, "each", notmuch_rb_filenames_each, 0); /* in filenames.c */
-    rb_include_module (notmuch_rb_cFileNames, rb_mEnumerable);
-
     /*
      * Document-class: Notmuch::Query
      *
@@ -395,15 +374,4 @@ Init_notmuch (void)
     rb_define_method (notmuch_rb_cMessage, "tags_to_maildir_flags", notmuch_rb_message_tags_to_maildir_flags, 0); /* in message.c */
     rb_define_method (notmuch_rb_cMessage, "freeze", notmuch_rb_message_freeze, 0); /* in message.c */
     rb_define_method (notmuch_rb_cMessage, "thaw", notmuch_rb_message_thaw, 0); /* in message.c */
-
-    /*
-     * Document-class: Notmuch::Tags
-     *
-     * Notmuch tags
-     */
-    notmuch_rb_cTags = rb_define_class_under (mod, "Tags", rb_cObject);
-    rb_undef_method (notmuch_rb_cTags, "initialize");
-    rb_define_method (notmuch_rb_cTags, "destroy!", notmuch_rb_tags_destroy, 0); /* in tags.c */
-    rb_define_method (notmuch_rb_cTags, "each", notmuch_rb_tags_each, 0); /* in tags.c */
-    rb_include_module (notmuch_rb_cTags, rb_mEnumerable);
 }
diff --git a/bindings/ruby/message.c b/bindings/ruby/message.c
index f45c95cc..13c182f6 100644
--- a/bindings/ruby/message.c
+++ b/bindings/ruby/message.c
@@ -120,7 +120,7 @@ notmuch_rb_message_get_filenames (VALUE self)
 
     fnames = notmuch_message_get_filenames (message);
 
-    return Data_Wrap_Notmuch_Object (notmuch_rb_cFileNames, &notmuch_rb_filenames_type, fnames);
+    return notmuch_rb_filenames_get (fnames);
 }
 
 /*
@@ -221,7 +221,7 @@ notmuch_rb_message_get_tags (VALUE self)
     if (!tags)
 	rb_raise (notmuch_rb_eMemoryError, "Out of memory");
 
-    return Data_Wrap_Notmuch_Object (notmuch_rb_cTags, &notmuch_rb_tags_type, tags);
+    return notmuch_rb_tags_get (tags);
 }
 
 /*
diff --git a/bindings/ruby/messages.c b/bindings/ruby/messages.c
index ca5b10d0..6369d052 100644
--- a/bindings/ruby/messages.c
+++ b/bindings/ruby/messages.c
@@ -71,5 +71,5 @@ notmuch_rb_messages_collect_tags (VALUE self)
     if (!tags)
 	rb_raise (notmuch_rb_eMemoryError, "Out of memory");
 
-    return Data_Wrap_Notmuch_Object (notmuch_rb_cTags, &notmuch_rb_tags_type, tags);
+    return notmuch_rb_tags_get (tags);
 }
diff --git a/bindings/ruby/query.c b/bindings/ruby/query.c
index 8a2b4d3d..077def02 100644
--- a/bindings/ruby/query.c
+++ b/bindings/ruby/query.c
@@ -45,7 +45,7 @@ notmuch_rb_query_get_sort (VALUE self)
 
     Data_Get_Notmuch_Query (self, query);
 
-    return FIX2INT (notmuch_query_get_sort (query));
+    return INT2FIX (notmuch_query_get_sort (query));
 }
 
 /*
diff --git a/bindings/ruby/tags.c b/bindings/ruby/tags.c
index 2af85e36..b64874d1 100644
--- a/bindings/ruby/tags.c
+++ b/bindings/ruby/tags.c
@@ -1,56 +1,13 @@
-/* The Ruby interface to the notmuch mail library
- *
- * Copyright © 2010, 2011 Ali Polatel
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see https://www.gnu.org/licenses/ .
- *
- * Author: Ali Polatel <alip@exherbo.org>
- */
-
 #include "defs.h"
 
-/*
- * call-seq: TAGS.destroy! => nil
- *
- * Destroys the tags, freeing all resources allocated for it.
- */
 VALUE
-notmuch_rb_tags_destroy (VALUE self)
+notmuch_rb_tags_get (notmuch_tags_t *tags)
 {
-    notmuch_rb_object_destroy (self, &notmuch_rb_tags_type);
-
-    return Qnil;
-}
-
-/*
- * call-seq: TAGS.each {|item| block } => TAGS
- *
- * Calls +block+ once for each element in +self+, passing that element as a
- * parameter.
- */
-VALUE
-notmuch_rb_tags_each (VALUE self)
-{
-    const char *tag;
-    notmuch_tags_t *tags;
-
-    Data_Get_Notmuch_Tags (self, tags);
+    VALUE rb_array = rb_ary_new ();
 
     for (; notmuch_tags_valid (tags); notmuch_tags_move_to_next (tags)) {
-	tag = notmuch_tags_get (tags);
-	rb_yield (rb_str_new2 (tag));
+	const char *tag = notmuch_tags_get (tags);
+	rb_ary_push (rb_array, rb_str_new2 (tag));
     }
-
-    return self;
+    return rb_array;
 }
diff --git a/bindings/ruby/thread.c b/bindings/ruby/thread.c
index 7cb2a3dc..b20ed893 100644
--- a/bindings/ruby/thread.c
+++ b/bindings/ruby/thread.c
@@ -204,5 +204,5 @@ notmuch_rb_thread_get_tags (VALUE self)
     if (!tags)
 	rb_raise (notmuch_rb_eMemoryError, "Out of memory");
 
-    return Data_Wrap_Notmuch_Object (notmuch_rb_cTags, &notmuch_rb_tags_type, tags);
+    return notmuch_rb_tags_get (tags);
 }
diff --git a/compat/have_strcasestr.c b/compat/have_strcasestr.c
index 3cd1838d..8e004572 100644
--- a/compat/have_strcasestr.c
+++ b/compat/have_strcasestr.c
@@ -1,5 +1,6 @@
 #define _GNU_SOURCE
-#include <strings.h>
+#include <strings.h> /* strcasecmp() in POSIX */
+#include <string.h> /* strcasecmp() in *BSD */
 
 int
 main ()
diff --git a/completion/notmuch-completion.bash b/completion/notmuch-completion.bash
index 0022b54b..3748846e 100644
--- a/completion/notmuch-completion.bash
+++ b/completion/notmuch-completion.bash
@@ -530,7 +530,7 @@ _notmuch_show()
     ! $split &&
     case "${cur}" in
 	-*)
-	    local options="--entire-thread= --format= --exclude= --body= --format-version= --part= --verify --decrypt= --include-html ${_notmuch_shared_options}"
+	    local options="--entire-thread= --format= --exclude= --body= --format-version= --part= --verify --decrypt= --include-html --limit= --offset= ${_notmuch_shared_options}"
 	    compopt -o nospace
 	    COMPREPLY=( $(compgen -W "$options" -- ${cur}) )
 	    ;;
diff --git a/completion/zsh/_notmuch b/completion/zsh/_notmuch
index e207d90b..0bdd7f77 100644
--- a/completion/zsh/_notmuch
+++ b/completion/zsh/_notmuch
@@ -245,6 +245,8 @@ _notmuch_show() {
     '--exclude=[respect excluded tags setting]:exclude tags:(true false)' \
     '--body=[output body]:output body content:(true false)' \
     '--include-html[include text/html parts in the output]' \
+    '--limit=[limit the number of displayed results]:limit: ' \
+    '--offset=[skip displaying the first N results]:offset: ' \
     '*::search term:_notmuch_search_term'
 }
 
diff --git a/configure b/configure
index be69b34d..7afd08c7 100755
--- a/configure
+++ b/configure
@@ -422,6 +422,18 @@ else
 fi
 unset test_cmdline
 
+printf "C compiler supports thread sanitizer... "
+test_cmdline="${CC} ${CFLAGS} ${CPPFLAGS} -fsanitize=thread minimal.c ${LDFLAGS} -o minimal"
+if ${test_cmdline} >/dev/null 2>&1 && ./minimal
+then
+    printf "Yes.\n"
+    have_tsan=1
+else
+    printf "Nope, skipping those tests.\n"
+    have_tsan=0
+fi
+unset test_cmdline
+
 printf "Reading libnotmuch version from source... "
 cat > _libversion.c <<EOF
 #include <stdio.h>
@@ -541,8 +553,8 @@ version of GPGME.
 Please try to rebuild your version of GMime against a more recent
 version of GPGME (at least GPGME 1.8.0).
 EOF
-	if command -v gpgme-config >/dev/null; then
-	    printf 'Your current GPGME development version is: %s\n' "$(gpgme-config --version)"
+	if GPGME_VERS="$(pkg-config --modversion gpgme || gpgme-config --version)"; then
+	    printf 'Your current GPGME development version is: %s\n' "$GPGME_VERS"
 	else
 	    printf 'You do not have the GPGME development libraries installed.\n'
 	fi
@@ -1590,8 +1602,9 @@ NOTMUCH_GMIME_VERIFY_WITH_SESSION_KEY=${gmime_verify_with_session_key}
 NOTMUCH_ZLIB_CFLAGS="${zlib_cflags}"
 NOTMUCH_ZLIB_LDFLAGS="${zlib_ldflags}"
 
-# Does the C compiler support the address sanitizer
+# Does the C compiler support the sanitizers
 NOTMUCH_HAVE_ASAN=${have_asan}
+NOTMUCH_HAVE_TSAN=${have_tsan}
 
 # do we have man pages?
 NOTMUCH_HAVE_MAN=$((have_sphinx))
diff --git a/contrib/notmuch-mutt/README b/contrib/notmuch-mutt/README
index 26996c4a..c7520228 100644
--- a/contrib/notmuch-mutt/README
+++ b/contrib/notmuch-mutt/README
@@ -39,8 +39,6 @@ To *run* notmuch-mutt you will need Perl with the following libraries:
   (Debian package: libmail-box-perl)
 - Mail::Header <https://metacpan.org/pod/Mail::Header>
   (Debian package: libmailtools-perl)
-- String::ShellQuote <https://metacpan.org/pod/String::ShellQuote>
-  (Debian package: libstring-shellquote-perl)
 - Term::ReadLine::Gnu <https://metacpan.org/pod/Term::ReadLine::Gnu>
   (Debian package: libterm-readline-gnu-perl)
 
diff --git a/contrib/notmuch-mutt/notmuch-mutt b/contrib/notmuch-mutt/notmuch-mutt
index d1e2c084..1ac68065 100755
--- a/contrib/notmuch-mutt/notmuch-mutt
+++ b/contrib/notmuch-mutt/notmuch-mutt
@@ -2,7 +2,7 @@
 #
 # notmuch-mutt - notmuch (of a) helper for Mutt
 #
-# Copyright: © 2011-2015 Stefano Zacchiroli <zack@upsilon.cc>
+# Copyright: © 2011-2015 Stefano Zacchiroli <zack@upsilon.cc>
 # License: GNU General Public License (GPL), version 3 or above
 #
 # See the bottom of this file for more documentation.
@@ -13,11 +13,11 @@ use warnings;
 
 use File::Path;
 use File::Basename;
+use File::Find;
 use Getopt::Long qw(:config no_getopt_compat);
 use Mail::Header;
 use Mail::Box::Maildir;
 use Pod::Usage;
-use String::ShellQuote;
 use Term::ReadLine;
 use Digest::SHA;
 
@@ -26,9 +26,53 @@ my $xdg_cache_dir = "$ENV{HOME}/.cache";
 $xdg_cache_dir = $ENV{XDG_CACHE_HOME} if $ENV{XDG_CACHE_HOME};
 my $cache_dir = "$xdg_cache_dir/notmuch/mutt";
 
+sub die_dir($$) {
+    my ($maildir, $error) = @_;
+    die "notmuch-mutt: search cache maildir $maildir $error\n".
+        "Please ensure that the notmuch-mutt search cache Maildir\n".
+        "contains no subfolders or real mail data, only symlinks to mail\n";
+}
 
-# create an empty maildir (if missing) or empty an existing maildir"
-sub empty_maildir($) {
+sub die_subdir($$$) {
+    my ($maildir, $subdir, $error) = @_;
+    die_dir($maildir, "subdir $subdir $error");
+}
+
+# check that the search cache maildir is that and not a real maildir
+# otherwise there could be data loss when the search cache is emptied
+sub check_search_cache_maildir($) {
+    my ($maildir) = (@_);
+
+    return unless -e $maildir;
+
+    -d $maildir or die_dir($maildir, 'is not a directory');
+
+    opendir(my $mdh, $maildir) or die_dir($maildir, "cannot be opened: $!");
+    my @contents = grep { !/^\.\.?$/ } readdir $mdh;
+    closedir $mdh;
+
+    my @required = ('cur', 'new', 'tmp');
+    foreach my $d (@required) {
+        -l "$maildir/$d" and die_dir($maildir, "contains symlink $d");
+        -e "$maildir/$d" or die_subdir($maildir, $d, 'is missing');
+        -d "$maildir/$d" or die_subdir($maildir, $d, 'is not a directory');
+        find(sub {
+            $_ eq '.' and return;
+            $_ eq '..' and return;
+            -l $_ or die_subdir($maildir, $d, "contains non-symlink $_");
+        }, "$maildir/$d");
+    }
+
+    my %required = map { $_ => 1 } @required;
+    foreach my $d (@contents) {
+        -l "$maildir/$d" and die_dir( $maildir, "contains symlink $d");
+        -d "$maildir/$d" or die_dir( $maildir, "contains non-directory $d");
+        exists($required[$d]) or die_dir( $maildir, "contains directory $d");
+    }
+}
+
+# create an empty search cache maildir (if missing) or empty existing one
+sub empty_search_cache_maildir($) {
     my ($maildir) = (@_);
     rmtree($maildir) if (-d $maildir);
     my $folder = new Mail::Box::Maildir(folder => $maildir,
@@ -46,7 +90,8 @@ sub search($$$) {
     push @args, "--duplicate=1" if $remove_dups;
     push @args, $query;
 
-    empty_maildir($maildir);
+    check_search_cache_maildir($maildir);
+    empty_search_cache_maildir($maildir);
     open my $pipe, '-|', @args or die "Running @args failed: $!\n";
     while (<$pipe>) {
 	chomp;
@@ -121,21 +166,23 @@ sub thread_action($$@) {
 
     my $mid = get_message_id();
     if (! defined $mid) {
-	empty_maildir($results_dir);
 	die "notmuch-mutt: cannot find Message-Id, abort.\n";
     }
-    my $search_cmd = 'notmuch search --output=threads ' . shell_quote("id:$mid");
-    my $tid = `$search_cmd`;	# get thread id
-    chomp($tid);
 
-    search($results_dir, $remove_dups, $tid);
+    $mid =~ s/ //g; # notmuch strips spaces before storing Message-Id
+    $mid =~ s/"/""""/g; # escape all double quote characters twice
+
+    search($results_dir, $remove_dups, qq{thread:"{id:""$mid""}"});
 }
 
 sub tag_action(@) {
     my $mid = get_message_id();
     defined $mid or die "notmuch-mutt: cannot find Message-Id, abort.\n";
 
-    system("notmuch", "tag", @_, "--", "id:$mid");
+    $mid =~ s/ //g; # notmuch strips spaces before storing Message-Id
+    $mid =~ s/"/""/g; # escape all double quote characters
+
+    system("notmuch", "tag", @_, "--", qq{id:"$mid"});
 }
 
 sub die_usage() {
diff --git a/debian/changelog b/debian/changelog
index 846ccd2e..c2c2f6ab 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,42 @@
+notmuch (0.38-2) unstable; urgency=medium
+
+  * Restrict autopkgtests to amd64 and aarch64. There are failures in
+    remaining architectures, but the same tests pass at build time, so any
+    bugs are probably related to either the autopkgtest environment, or
+    the (new) upstream test runner for installed notmuch.
+
+ -- David Bremner <bremner@debian.org>  Wed, 13 Sep 2023 19:55:00 -0300
+
+notmuch (0.38-1) unstable; urgency=medium
+
+  * New upstream release
+  * Bug fix: "FTBFS: 6 tests failed.", thanks to Aurelien Jarno (Closes:
+    #1051111).
+  * Run most of upstream test suite as autopkgtests
+
+ -- David Bremner <bremner@debian.org>  Tue, 12 Sep 2023 08:33:24 -0300
+
+notmuch (0.38~rc2-1) experimental; urgency=medium
+
+  * New upstream release candidate
+
+ -- David Bremner <bremner@debian.org>  Sun, 03 Sep 2023 09:10:24 -0300
+
+notmuch (0.38~rc1-1) experimental; urgency=medium
+
+  * New upstream release candidate
+  * Hopefully reduce/eliminate intermittent failures of T460 by
+    controlling Emacs native compilation.
+  * Disable T810-tsan on ppc64el
+
+ -- David Bremner <bremner@debian.org>  Sat, 26 Aug 2023 08:31:21 -0300
+
+notmuch (0.38~rc0-1) experimental; urgency=medium
+
+  * New upstream release candidate
+
+ -- David Bremner <bremner@debian.org>  Thu, 24 Aug 2023 10:56:06 -0300
+
 notmuch (0.37-1) unstable; urgency=medium
 
   * New upstream release.
diff --git a/debian/control b/debian/control
index 2dcb8cc7..135eb7ce 100644
--- a/debian/control
+++ b/debian/control
@@ -227,7 +227,6 @@ Architecture: all
 Depends:
  libmail-box-perl,
  libmailtools-perl,
- libstring-shellquote-perl,
  libterm-readline-gnu-perl,
  notmuch (>= 0.4),
  ${misc:Depends},
diff --git a/debian/rules b/debian/rules
index f9196b82..a77ffa15 100755
--- a/debian/rules
+++ b/debian/rules
@@ -1,4 +1,9 @@
 #!/usr/bin/make -f
+include /usr/share/dpkg/architecture.mk
+
+ifeq ($(DEB_HOST_ARCH),ppc64el)
+	export NOTMUCH_SKIP_TESTS = T810-tsan
+endif
 
 export DEB_BUILD_MAINT_OPTIONS = hardening=+all
 
@@ -7,7 +12,7 @@ export DEB_BUILD_MAINT_OPTIONS = hardening=+all
 
 override_dh_auto_configure:
 	BASHCMD=/bin/bash ./configure --prefix=/usr \
-		--libdir=/usr/lib/$$(dpkg-architecture -q DEB_TARGET_MULTIARCH) \
+		--libdir=/usr/lib/${DEB_TARGET_MULTIARCH} \
 		--includedir=/usr/include \
 		--mandir=/usr/share/man \
 		--infodir=/usr/share/info \
@@ -24,7 +29,6 @@ override_dh_auto_build:
 override_dh_auto_clean:
 	dh_auto_clean
 	PYBUILD_NAME=notmuch dh_auto_clean --buildsystem=pybuild --sourcedirectory bindings/python
-	PYBUILD_NAME=notmuch2 dh_auto_clean --buildsystem=pybuild --sourcedirectory bindings/python-cffi
 	dh_auto_clean --sourcedirectory bindings/ruby
 	$(MAKE) -C contrib/notmuch-mutt clean
 
diff --git a/debian/tests/control b/debian/tests/control
new file mode 100644
index 00000000..80be1deb
--- /dev/null
+++ b/debian/tests/control
@@ -0,0 +1,18 @@
+Test-command: env NOTMUCH_TEST_INSTALLED=1 TERM=dumb
+    NOTMUCH_HAVE_MAN=1 NOTMUCH_HAVE_SFSEXP=1 NOTMUCH_HAVE_XAPIAN_DB_RETRY_LOCK=1
+    NOTMUCH_HAVE_PYTHON3_CFFI=1 NOTMUCH_HAVE_PYTHON3_PYTEST=1
+    NOTMUCH_HAVE_ASAN=1 NOTMUCH_HAVE_TSAN=1
+    ./test/notmuch-test
+Restrictions: allow-stderr
+Architecture: amd64, arm64
+Depends: @,
+ build-essential,
+ dtach,
+ emacs-nox,
+ gdb,
+ git,
+ gnupg,
+ gpgsm,
+ libtalloc-dev,
+ man,
+ xapian-tools
diff --git a/devel/schemata b/devel/schemata
index 66bcdbed..4e05cdac 100644
--- a/devel/schemata
+++ b/devel/schemata
@@ -76,6 +76,7 @@ message = {
     # (format_message_sprinter)
     id:             messageid,
     match:          bool,
+    excluded:       bool,
     filename:	    [string*],
     timestamp:      unix_time, # date header as unix time
     date_relative:  string,   # user-friendly timestamp
diff --git a/doc/Makefile.local b/doc/Makefile.local
index 51c729cf..aafa77a0 100644
--- a/doc/Makefile.local
+++ b/doc/Makefile.local
@@ -159,3 +159,5 @@ $(dir)/config.dox: version.stamp
 CLEAN := $(CLEAN) $(DOCBUILDDIR) $(DOCBUILDDIR)/.roff.stamp $(DOCBUILDDIR)/.texi.stamp
 CLEAN := $(CLEAN) $(DOCBUILDDIR)/.html.stamp $(DOCBUILDDIR)/.info.stamp
 CLEAN := $(CLEAN) $(MAN_GZIP_FILES) $(MAN_ROFF_FILES) $(dir)/conf.pyc $(dir)/config.dox
+
+CLEAN := $(CLEAN) $(dir)/__pycache__
diff --git a/doc/conf.py b/doc/conf.py
index e23cb7d7..7ac13a5d 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -16,7 +16,7 @@ master_doc = 'index'
 
 # General information about the project.
 project = u'notmuch'
-copyright = u'2009-2022, Carl Worth and many others'
+copyright = u'2009-2023, Carl Worth and many others'
 
 location = os.path.dirname(__file__)
 
diff --git a/doc/man1/notmuch-config.rst b/doc/man1/notmuch-config.rst
index 388315f6..bd34afa4 100644
--- a/doc/man1/notmuch-config.rst
+++ b/doc/man1/notmuch-config.rst
@@ -122,6 +122,16 @@ paths are presumed relative to `$HOME` for items in section
 
     Default tag prefix (filter) for :any:`notmuch-git`.
 
+.. nmconfig:: index.as_text
+
+   List of regular expressions (without delimiters) for MIME types to
+   be indexed as text. Currently this applies only to attachments.  By
+   default the regex matches anywhere in the content type; if the
+   user wants an anchored match, they should include anchors in their
+   regexes.
+
+   History: This configuration value was introduced in notmuch 0.38.
+
 .. nmconfig:: index.decrypt
 
     Policy for decrypting encrypted messages during indexing.  Must be
diff --git a/doc/man1/notmuch-git.rst b/doc/man1/notmuch-git.rst
index ac1908b6..33a46f84 100644
--- a/doc/man1/notmuch-git.rst
+++ b/doc/man1/notmuch-git.rst
@@ -325,11 +325,11 @@ If it is unset, 'default' is assumed.
 
 .. envvar:: NOTMUCH_GIT_DIR
 
-   Default location of git repository. Overriden by :option:`--git-dir`.
+   Default location of git repository. Overridden by :option:`--git-dir`.
 
 .. envvar:: NOTMUCH_GIT_PREFIX
 
-   Default tag prefix (filter). Overriden by :option:`--tag-prefix`.
+   Default tag prefix (filter). Overridden by :option:`--tag-prefix`.
 
 SEE ALSO
 ========
diff --git a/doc/man1/notmuch-search.rst b/doc/man1/notmuch-search.rst
index ad305efd..b87737ea 100644
--- a/doc/man1/notmuch-search.rst
+++ b/doc/man1/notmuch-search.rst
@@ -43,7 +43,7 @@ Supported options for **search** include
 
 .. option:: --output=(summary|threads|messages|files|tags)
 
-   summary
+   summary (default)
      Output a summary of each thread with any message matching the
      search terms. The summary includes the thread ID, date, the
      number of messages in the thread (both the number matched and
diff --git a/doc/man1/notmuch-show.rst b/doc/man1/notmuch-show.rst
index 2c0a0de6..c13d94de 100644
--- a/doc/man1/notmuch-show.rst
+++ b/doc/man1/notmuch-show.rst
@@ -130,6 +130,15 @@ Supported options for **show** include
    By default, results will be displayed in reverse chronological
    order, (that is, the newest results will be displayed first).
 
+.. option:: --offset=[-]N
+
+   Skip displaying the first N results. With the leading '-', start
+   at the Nth result from the end.
+
+.. option:: --limit=N
+
+   Limit the number of displayed results to N.
+
 .. option:: --verify
 
    Compute and report the validity of any MIME cryptographic
diff --git a/doc/man7/notmuch-sexp-queries.rst b/doc/man7/notmuch-sexp-queries.rst
index 422154c7..858ff685 100644
--- a/doc/man7/notmuch-sexp-queries.rst
+++ b/doc/man7/notmuch-sexp-queries.rst
@@ -274,7 +274,7 @@ EXAMPLES
 
     Matches any word starting with "prelim", inside a message subject.
 
-``(subject (starts-wih quick) "brown fox")``
+``(subject (starts-with quick) "brown fox")``
 
     Match messages whose subject contains "quick brown fox", but also
     "brown fox quicksand".
@@ -336,7 +336,7 @@ user defined fields is permitted within a macro.
 NOTES
 =====
 
-.. [#macro-details] Technically macros impliment lazy evaluation and
+.. [#macro-details] Technically macros implement lazy evaluation and
                     lexical scope. There is one top level scope
                     containing all macro definitions, but all
                     parameter definitions are local to a given macro.
@@ -347,10 +347,10 @@ NOTES
 
 .. [#aka-bool] a.k.a. boolean prefixes
 
-.. [#not-phrase] Due to the implemention of phrase fields in Xapian,
+.. [#not-phrase] Due to the implementation of phrase fields in Xapian,
                  regex queries could only match individual words.
 
-.. [#not-body] Due the the way ``body`` is implemented in notmuch,
+.. [#not-body] Due to the way ``body`` is implemented in notmuch,
                this modifier is not supported in the ``body`` field.
 
 .. [#not-path] Due to the way recursive ``path`` queries are implemented
diff --git a/doc/notmuch-emacs.rst b/doc/notmuch-emacs.rst
index 846f5e67..7dff7d64 100644
--- a/doc/notmuch-emacs.rst
+++ b/doc/notmuch-emacs.rst
@@ -14,7 +14,7 @@ manual to refer to the Emacs interface to Notmuch. When this distinction
 is important, we’ll refer to the Emacs interface as
 *notmuch-emacs*.
 
-Notmuch-emacs is highly customizable via the the Emacs customization
+Notmuch-emacs is highly customizable via the Emacs customization
 framework (or just by setting the appropriate variables). We try to
 point out relevant variables in this manual, but in order to avoid
 duplication of information, you can usually find the most detailed
@@ -493,7 +493,7 @@ in :ref:`notmuch-search`.
 Dealing with duplicates
 -----------------------
 
-If there are are multiple files with the same :mailheader:`Message-ID`
+If there are multiple files with the same :mailheader:`Message-ID`
 (see :any:`duplicate-files`), then :any:`notmuch-show` displays the
 number of duplicates and identifies the current duplicate. In the
 following example duplicate 3 of 5 is displayed.
@@ -606,6 +606,45 @@ can be controlled by the variable ``notmuch-search-oldest-first``.
    See also :el:defcustom:`notmuch-search-result-format` and
    :el:defcustom:`notmuch-unthreaded-result-format`.
 
+.. _notmuch-tree-outline:
+
+notmuch-tree-outline
+--------------------
+
+When this mode is set, each thread and subthread in the results
+list is treated as a foldable section, with its first message as
+its header.
+
+The mode just makes available in the tree buffer all the
+keybindings in info:emacs#Outline_Mode, and binds the following
+additional keys:
+
+.. el:define-key:: <tab>
+
+   Cycle visibility state of the current message's tree.
+
+.. el:define-key:: <M-tab>
+
+   Cycle visibility state of all trees in the buffer.
+
+The behaviour of this minor mode is affected by the following
+customizable variables:
+
+.. el:defcustom:: notmuch-tree-outline-enabled
+
+   |docstring::notmuch-tree-outline-enabled|
+
+.. el:defcustom:: notmuch-tree-outline-visibility
+
+   |docstring::notmuch-tree-outline-visibility|
+
+.. el:defcustom:: notmuch-tree-outline-auto-close
+
+   |docstring::notmuch-tree-outline-auto-close|
+
+.. el:defcustom:: notmuch-tree-outline-open-on-next
+
+   |docstring::notmuch-tree-outline-open-on-next|
 
 .. _notmuch-unthreaded:
 
@@ -678,7 +717,7 @@ operations specified in ``notmuch-tagging-keys``; i.e. each
 notmuch-tag-undo
 ----------------
 
-Each notmuch buffer supporting tagging operations (i.e buffers in
+Each notmuch buffer supporting tagging operations (i.e. buffers in
 :any:`notmuch-show`, :any:`notmuch-search`, :any:`notmuch-tree`, and
 :any:`notmuch-unthreaded` mode) keeps a local stack of tagging
 operations. These can be undone via :any:`notmuch-tag-undo`. By default
diff --git a/emacs/notmuch-mua.el b/emacs/notmuch-mua.el
index ac878a61..3679d7d7 100644
--- a/emacs/notmuch-mua.el
+++ b/emacs/notmuch-mua.el
@@ -416,11 +416,6 @@ moved to the \"To:\" header."
     (let ((user-agent (funcall notmuch-mua-user-agent-function)))
       (unless (string-empty-p user-agent)
 	(push (cons 'User-Agent user-agent) other-headers))))
-  (unless (assq 'From other-headers)
-    (push (cons 'From (message-make-from
-		       (notmuch-user-name)
-		       (notmuch-user-primary-email)))
-	  other-headers))
   (notmuch-mua-pop-to-buffer (message-buffer-name "mail" to)
 			     (or switch-function
 				 (notmuch-mua-get-switch-function)))
@@ -439,6 +434,11 @@ moved to the \"To:\" header."
 	;; Cause `message-setup-1' to do things relevant for mail,
 	;; such as observe `message-default-mail-headers'.
 	(message-this-is-mail t))
+    (unless (assq 'From headers)
+      (push (cons 'From (message-make-from
+			 (notmuch-user-name)
+			 (notmuch-user-primary-email)))
+	    headers))
     (message-setup-1 headers yank-action send-actions return-action))
   (notmuch-fcc-header-setup)
   (notmuch-mua--remove-dont-reply-to-names)
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index ec998ede..36cce619 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -452,14 +452,19 @@ operation on the contents of the current buffer."
 (defun notmuch-show-update-tags (tags)
   "Update the displayed tags of the current message."
   (save-excursion
-    (goto-char (notmuch-show-message-top))
-    (when (re-search-forward "(\\([^()]*\\))$" (line-end-position) t)
-      (let ((inhibit-read-only t))
-	(replace-match (concat "("
-			       (notmuch-tag-format-tags
-				tags
-				(notmuch-show-get-prop :orig-tags))
-			       ")"))))))
+    (let ((inhibit-read-only t)
+	  (start (notmuch-show-message-top))
+	  (depth (notmuch-show-get-prop :depth))
+	  (orig-tags (notmuch-show-get-prop :orig-tags))
+	  (props (notmuch-show-get-message-properties))
+	  (extent (notmuch-show-message-extent)))
+      (goto-char start)
+      (notmuch-show-insert-headerline props depth tags orig-tags)
+      (put-text-property start (1+ start)
+			 :notmuch-message-properties props)
+      (put-text-property (car extent) (cdr extent) :notmuch-message-extent extent)
+      ;; delete original headerline, but do not save to kill ring
+      (delete-region (point) (1+ (line-end-position))))))
 
 (defun notmuch-clean-address (address)
   "Try to clean a single email ADDRESS for display. Return a cons
@@ -530,11 +535,17 @@ Return unchanged ADDRESS if parsing fails."
 	  (plist-put msg :height height)
 	  height))))
 
-(defun notmuch-show-insert-headerline (headers date tags depth duplicate file-count)
+(defun notmuch-show-insert-headerline (msg-plist depth tags &optional orig-tags)
   "Insert a notmuch style headerline based on HEADERS for a
 message at DEPTH in the current thread."
-  (let ((start (point))
-	(from (notmuch-sanitize
+  (let* ((start (point))
+	 (headers (plist-get msg-plist :headers))
+	 (duplicate (or (plist-get msg-plist :duplicate) 0))
+	 (file-count (length (plist-get msg-plist :filename)))
+	 (date (or (and notmuch-show-relative-dates
+			(plist-get msg-plist :date_relative))
+		   (plist-get headers :Date)))
+	 (from (notmuch-sanitize
 	       (notmuch-show-clean-address (plist-get headers :From)))))
     (when (string-match "\\cR" from)
       ;; If the From header has a right-to-left character add
@@ -549,7 +560,7 @@ message at DEPTH in the current thread."
 	    " ("
 	    date
 	    ") ("
-	    (notmuch-tag-format-tags tags tags)
+	    (notmuch-tag-format-tags tags (or orig-tags tags))
 	    ")")
     (insert
      (if (> file-count 1)
@@ -1171,8 +1182,6 @@ is out of range."
 (defun notmuch-show-insert-msg (msg depth)
   "Insert the message MSG at depth DEPTH in the current thread."
   (let* ((headers (plist-get msg :headers))
-	 (duplicate (or (plist-get msg :duplicate) 0))
-	 (files (length (plist-get msg :filename)))
 	 ;; Indentation causes the buffer offset of the start/end
 	 ;; points to move, so we must use markers.
 	 message-start message-end
@@ -1180,11 +1189,7 @@ is out of range."
 	 headers-start headers-end
 	 (bare-subject (notmuch-show-strip-re (plist-get headers :Subject))))
     (setq message-start (point-marker))
-    (notmuch-show-insert-headerline headers
-				    (or (and notmuch-show-relative-dates
-					     (plist-get msg :date_relative))
-					(plist-get headers :Date))
-				    (plist-get msg :tags) depth duplicate files)
+    (notmuch-show-insert-headerline msg depth (plist-get msg :tags))
     (setq content-start (point-marker))
     ;; Set `headers-start' to point after the 'Subject:' header to be
     ;; compatible with the existing implementation. This just sets it
diff --git a/emacs/notmuch-tree.el b/emacs/notmuch-tree.el
index b3c2c992..b58fa6a6 100644
--- a/emacs/notmuch-tree.el
+++ b/emacs/notmuch-tree.el
@@ -1014,7 +1014,10 @@ unchanged ADDRESS if parsing fails."
 A message tree is another name for a single sub-thread: i.e., a
 message together with all its descendents."
   (let ((msg (car tree))
-	(replies (cadr tree)))
+	(replies (cadr tree))
+	;; outline level, computed from the message's depth and
+	;; whether or not it's the first message in the tree.
+	(level (1+ (if (and (eq 0 depth) (not first)) 1 depth))))
     (cond
      ((and (< 0 depth) (not last))
       (push (alist-get 'vertical-tee  notmuch-tree-thread-symbols) tree-status))
@@ -1034,6 +1037,7 @@ message together with all its descendents."
     (setq msg (plist-put msg :first (and first (eq 0 depth))))
     (setq msg (plist-put msg :tree-status tree-status))
     (setq msg (plist-put msg :orig-tags (plist-get msg :tags)))
+    (setq msg (plist-put msg :level level))
     (notmuch-tree-goto-and-insert-msg msg)
     (pop tree-status)
     (pop tree-status)
@@ -1080,7 +1084,8 @@ Complete list of currently available key bindings:
   (setq notmuch-buffer-refresh-function #'notmuch-tree-refresh-view)
   (hl-line-mode 1)
   (setq buffer-read-only t)
-  (setq truncate-lines t))
+  (setq truncate-lines t)
+  (when notmuch-tree-outline-enabled (notmuch-tree-outline-mode 1)))
 
 (defvar notmuch-tree-process-exit-functions nil
   "Functions called when the process inserting a tree of results finishes.
@@ -1278,6 +1283,180 @@ search results and that are also tagged with the given TAG."
 		  nil
 		  notmuch-search-oldest-first)))
 
+;;; Tree outline mode
+;;;; Custom variables
+(defcustom notmuch-tree-outline-enabled nil
+  "Whether to automatically activate `notmuch-tree-outline-mode' in tree views."
+  :type 'boolean)
+
+(defcustom notmuch-tree-outline-visibility 'hide-others
+  "Default state of the forest outline for `notmuch-tree-outline-mode'.
+
+This variable controls the state of a forest initially and after
+a movement command.  If set to nil, all trees are displayed while
+the symbol hide-all indicates that all trees in the forest should
+be folded and hide-other that only the first one should be
+unfolded."
+  :type '(choice (const :tag "Show all" nil)
+		 (const :tag "Hide others" hide-others)
+		 (const :tag "Hide all" hide-all)))
+
+(defcustom notmuch-tree-outline-auto-close nil
+  "Close message and tree windows when moving past the last message."
+  :type 'boolean)
+
+(defcustom notmuch-tree-outline-open-on-next nil
+  "Open new messages under point if they are closed when moving to next one.
+
+When this flag is set, using the command
+`notmuch-tree-outline-next' with point on a header for a new
+message that is not shown will open its `notmuch-show' buffer
+instead of moving point to next matching message."
+  :type 'boolean)
+
+;;;; Helper functions
+(defsubst notmuch-tree-outline--pop-at-end (pop-at-end)
+  (if notmuch-tree-outline-auto-close (not pop-at-end) pop-at-end))
+
+(defun notmuch-tree-outline--set-visibility ()
+  (when (and notmuch-tree-outline-mode (> (point-max) (point-min)))
+    (cl-case notmuch-tree-outline-visibility
+      (hide-others (notmuch-tree-outline-hide-others))
+      (hide-all (outline-hide-body)))))
+
+(defun notmuch-tree-outline--on-exit (proc)
+  (when (eq (process-status proc) 'exit)
+    (notmuch-tree-outline--set-visibility)))
+
+(add-hook 'notmuch-tree-process-exit-functions #'notmuch-tree-outline--on-exit)
+
+(defsubst notmuch-tree-outline--level (&optional props)
+  (or (plist-get (or props (notmuch-tree-get-message-properties)) :level) 0))
+
+(defsubst notmuch-tree-outline--message-open-p ()
+  (and (buffer-live-p notmuch-tree-message-buffer)
+       (get-buffer-window notmuch-tree-message-buffer)
+       (let ((id (notmuch-tree-get-message-id)))
+	 (and id
+	      (with-current-buffer notmuch-tree-message-buffer
+		(string= (notmuch-show-get-message-id) id))))))
+
+(defsubst notmuch-tree-outline--at-original-match-p ()
+  (and (notmuch-tree-get-prop :match)
+       (equal (notmuch-tree-get-prop :orig-tags)
+              (notmuch-tree-get-prop :tags))))
+
+(defun notmuch-tree-outline--next (prev thread pop-at-end &optional open-new)
+  (cond (thread
+	 (notmuch-tree-thread-top)
+	 (if prev
+	     (outline-backward-same-level 1)
+	   (outline-forward-same-level 1))
+	 (when (> (notmuch-tree-outline--level) 0) (outline-show-branches))
+	 (notmuch-tree-outline--next nil nil pop-at-end t))
+	((and (or open-new notmuch-tree-outline-open-on-next)
+	      (notmuch-tree-outline--at-original-match-p)
+	      (not (notmuch-tree-outline--message-open-p)))
+	 (notmuch-tree-outline-hide-others t))
+	(t (outline-next-visible-heading (if prev -1 1))
+	   (unless (notmuch-tree-get-prop :match)
+	     (notmuch-tree-matching-message prev pop-at-end))
+	   (notmuch-tree-outline-hide-others t))))
+
+;;;; User commands
+(defun notmuch-tree-outline-hide-others (&optional and-show)
+  "Fold all threads except the one around point.
+If AND-SHOW is t, make the current message visible if it's not."
+  (interactive)
+  (save-excursion
+    (while (and (not (bobp)) (> (notmuch-tree-outline--level) 1))
+      (outline-previous-heading))
+    (outline-hide-sublevels 1))
+  (when (> (notmuch-tree-outline--level) 0)
+    (outline-show-subtree)
+    (when and-show (notmuch-tree-show-message nil))))
+
+(defun notmuch-tree-outline-next (&optional pop-at-end)
+  "Next matching message in a forest, taking care of thread visibility.
+A prefix argument reverses the meaning of `notmuch-tree-outline-auto-close'."
+  (interactive "P")
+  (let ((pop (notmuch-tree-outline--pop-at-end pop-at-end)))
+    (if (null notmuch-tree-outline-visibility)
+	(notmuch-tree-matching-message nil pop)
+      (notmuch-tree-outline--next nil nil pop))))
+
+(defun notmuch-tree-outline-previous (&optional pop-at-end)
+  "Previous matching message in forest, taking care of thread visibility.
+With prefix, quit the tree view if there is no previous message."
+  (interactive "P")
+  (if (null notmuch-tree-outline-visibility)
+      (notmuch-tree-prev-matching-message pop-at-end)
+    (notmuch-tree-outline--next t nil pop-at-end)))
+
+(defun notmuch-tree-outline-next-thread ()
+  "Next matching thread in forest, taking care of thread visibility."
+  (interactive)
+  (if (null notmuch-tree-outline-visibility)
+      (notmuch-tree-next-thread)
+    (notmuch-tree-outline--next nil t nil)))
+
+(defun notmuch-tree-outline-previous-thread ()
+  "Previous matching thread in forest, taking care of thread visibility."
+  (interactive)
+  (if (null notmuch-tree-outline-visibility)
+      (notmuch-tree-prev-thread)
+    (notmuch-tree-outline--next t t nil)))
+
+;;;; Mode definition
+(defvar notmuch-tree-outline-mode-lighter nil
+  "The lighter mark for notmuch-tree-outline mode.
+Usually empty since outline-minor-mode's lighter will be active.")
+
+(define-minor-mode notmuch-tree-outline-mode
+  "Minor mode allowing message trees to be folded as outlines.
+
+When this mode is set, each thread and subthread in the results
+list is treated as a foldable section, with its first message as
+its header.
+
+The mode just makes available in the tree buffer all the
+keybindings in `outline-minor-mode', and binds the following
+additional keys:
+
+\\{notmuch-tree-outline-mode-map}
+
+The customizable variable `notmuch-tree-outline-visibility'
+controls how navigation in the buffer is affected by this mode:
+
+  - If it is set to nil, `notmuch-tree-outline-previous',
+    `notmuch-tree-outline-next', and their thread counterparts
+    behave just as the corresponding notmuch-tree navigation keys
+    when this mode is not enabled.
+
+  - If, on the other hand, `notmuch-tree-outline-visibility' is
+    set to a non-nil value, these commands hiding the outlines of
+    the trees you are not reading as you move to new messages.
+
+To enable notmuch-tree-outline-mode by default in all
+notmuch-tree buffers, just set
+`notmuch-tree-outline-mode-enabled' to t."
+  :lighter notmuch-tree-outline-mode-lighter
+  :keymap `((,(kbd "TAB") . outline-cycle)
+	    (,(kbd "M-TAB") . outline-cycle-buffer)
+	    ("n" . notmuch-tree-outline-next)
+	    ("p" . notmuch-tree-outline-previous)
+	    (,(kbd "M-n") . notmuch-tree-outline-next-thread)
+	    (,(kbd "M-p") . notmuch-tree-outline-previous-thread))
+  (outline-minor-mode notmuch-tree-outline-mode)
+  (unless (derived-mode-p 'notmuch-tree-mode)
+    (user-error "notmuch-tree-outline-mode is only meaningful for notmuch trees!"))
+  (if notmuch-tree-outline-mode
+      (progn (setq-local outline-regexp "^[^\n]+")
+	     (setq-local outline-level #'notmuch-tree-outline--level)
+	     (notmuch-tree-outline--set-visibility))
+    (setq-local outline-regexp (default-value 'outline-regexp))
+    (setq-local	outline-level (default-value 'outline-level))))
+
 ;;; _
 
 (provide 'notmuch-tree)
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index 26181758..6eef4af1 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -841,6 +841,7 @@ non-authors is found, assume that all of the authors match."
 	      overlay)
 	  (insert invisible-string)
 	  (setq overlay (make-overlay start (point)))
+	  (overlay-put overlay 'evaporate t)
 	  (overlay-put overlay 'invisible 'ellipsis)
 	  (overlay-put overlay 'isearch-open-invisible #'delete-overlay)))
       (insert padding))))
diff --git a/lib/config.cc b/lib/config.cc
index 503a0c8b..2323860d 100644
--- a/lib/config.cc
+++ b/lib/config.cc
@@ -599,6 +599,8 @@ _notmuch_config_key_to_string (notmuch_config_key_t key)
 	return "database.autocommit";
     case NOTMUCH_CONFIG_EXTRA_HEADERS:
 	return "show.extra_headers";
+    case NOTMUCH_CONFIG_INDEX_AS_TEXT:
+	return "index.as_text";
     default:
 	return NULL;
     }
@@ -642,6 +644,7 @@ _notmuch_config_default (notmuch_database_t *notmuch, notmuch_config_key_t key)
 	else
 	    email = _get_email_from_passwd_file (notmuch);
 	return email;
+    case NOTMUCH_CONFIG_INDEX_AS_TEXT:
     case NOTMUCH_CONFIG_NEW_IGNORE:
 	return "";
     case NOTMUCH_CONFIG_AUTOCOMMIT:
diff --git a/lib/database-private.h b/lib/database-private.h
index b9be4e22..61232f1a 100644
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -291,6 +291,10 @@ struct _notmuch_database {
 
     /* Track what parameters were specified when opening */
     notmuch_open_param_t params;
+
+    /* list of regular expressions to check for text indexing */
+    regex_t *index_as_text;
+    size_t index_as_text_length;
 };
 
 /* Prior to database version 3, features were implied by the database
diff --git a/lib/database.cc b/lib/database.cc
index c05d70d3..737a3f30 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -1454,9 +1454,11 @@ notmuch_database_remove_message (notmuch_database_t *notmuch,
 							&message);
 
     if (status == NOTMUCH_STATUS_SUCCESS && message) {
-	status = _notmuch_message_remove_filename (message, filename);
+	if (notmuch_message_count_files (message) > 1) {
+	    status = _notmuch_message_remove_filename (message, filename);
+	}
 	if (status == NOTMUCH_STATUS_SUCCESS)
-	    _notmuch_message_delete (message);
+	    status = _notmuch_message_delete (message);
 	else if (status == NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID)
 	    _notmuch_message_sync (message);
 
@@ -1573,3 +1575,15 @@ notmuch_database_status_string (const notmuch_database_t *notmuch)
 {
     return notmuch->status_string;
 }
+
+bool
+_notmuch_database_indexable_as_text (notmuch_database_t *notmuch, const char *mime_string)
+{
+    for (size_t i = 0; i < notmuch->index_as_text_length; i++) {
+	if (regexec (&notmuch->index_as_text[i], mime_string, 0, NULL, 0) == 0) {
+	    return true;
+	}
+    }
+
+    return false;
+}
diff --git a/lib/index.cc b/lib/index.cc
index 728bfb22..629dcb22 100644
--- a/lib/index.cc
+++ b/lib/index.cc
@@ -380,6 +380,23 @@ _index_pkcs7_part (notmuch_message_t *message,
 		   GMimeObject *part,
 		   _notmuch_message_crypto_t *msg_crypto);
 
+static bool
+_indexable_as_text (notmuch_message_t *message, GMimeObject *part)
+{
+    GMimeContentType *content_type = g_mime_object_get_content_type (part);
+    notmuch_database_t *notmuch = notmuch_message_get_database (message);
+
+    if (content_type) {
+	char *mime_string = g_mime_content_type_get_mime_type (content_type);
+	if (mime_string) {
+	    bool ret = _notmuch_database_indexable_as_text (notmuch, mime_string);
+	    g_free (mime_string);
+	    return ret;
+	}
+    }
+    return false;
+}
+
 /* Callback to generate terms for each mime part of a message. */
 static void
 _index_mime_part (notmuch_message_t *message,
@@ -497,9 +514,11 @@ _index_mime_part (notmuch_message_t *message,
 	_notmuch_message_add_term (message, "tag", "attachment");
 	_notmuch_message_gen_terms (message, "attachment", filename);
 
-	/* XXX: Would be nice to call out to something here to parse
-	 * the attachment into text and then index that. */
-	goto DONE;
+	if (! _indexable_as_text (message, part)) {
+	    /* XXX: Would be nice to call out to something here to parse
+	     * the attachment into text and then index that. */
+	    goto DONE;
+	}
     }
 
     byte_array = g_byte_array_new ();
diff --git a/lib/message-property.cc b/lib/message-property.cc
index d5afa30c..7f520340 100644
--- a/lib/message-property.cc
+++ b/lib/message-property.cc
@@ -25,6 +25,20 @@
 #include "database-private.h"
 #include "message-private.h"
 
+#define LOG_XAPIAN_EXCEPTION(message, error) _log_xapian_exception (__location__, message, error)
+
+static void
+_log_xapian_exception (const char *where, notmuch_message_t *message,  const Xapian::Error error)
+{
+    notmuch_database_t *notmuch = notmuch_message_get_database (message);
+
+    _notmuch_database_log (notmuch,
+			   "A Xapian exception occurred at %s: %s\n",
+			   where,
+			   error.get_msg ().c_str ());
+    notmuch->exception_reported = true;
+}
+
 notmuch_status_t
 notmuch_message_get_property (notmuch_message_t *message, const char *key, const char **value)
 {
@@ -83,10 +97,15 @@ _notmuch_message_modify_property (notmuch_message_t *message, const char *key, c
 
     term = talloc_asprintf (message, "%s=%s", key, value);
 
-    if (delete_it)
-	private_status = _notmuch_message_remove_term (message, "property", term);
-    else
-	private_status = _notmuch_message_add_term (message, "property", term);
+    try {
+	if (delete_it)
+	    private_status = _notmuch_message_remove_term (message, "property", term);
+	else
+	    private_status = _notmuch_message_add_term (message, "property", term);
+    } catch (Xapian::Error &error) {
+	LOG_XAPIAN_EXCEPTION (message, error);
+	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+    }
 
     if (private_status)
 	return COERCE_STATUS (private_status,
@@ -123,15 +142,22 @@ _notmuch_message_remove_all_properties (notmuch_message_t *message, const char *
     if (status)
 	return status;
 
-    _notmuch_message_invalidate_metadata (message, "property");
     if (key)
 	term_prefix = talloc_asprintf (message, "%s%s%s", _find_prefix ("property"), key,
 				       prefix ? "" : "=");
     else
 	term_prefix = _find_prefix ("property");
 
-    /* XXX better error reporting ? */
-    _notmuch_message_remove_terms (message, term_prefix);
+    try {
+	/* XXX better error reporting ? */
+	_notmuch_message_remove_terms (message, term_prefix);
+    } catch (Xapian::Error &error) {
+	LOG_XAPIAN_EXCEPTION (message, error);
+	return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+    }
+
+    if (! _notmuch_message_frozen (message))
+	_notmuch_message_sync (message);
 
     return NOTMUCH_STATUS_SUCCESS;
 }
diff --git a/lib/message.cc b/lib/message.cc
index 1c87f8c0..46638f80 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -719,6 +719,8 @@ _notmuch_message_remove_terms (notmuch_message_t *message, const char *prefix)
 	    /* Ignore failure to remove non-existent term. */
 	}
     }
+
+    _notmuch_message_invalidate_metadata (message, "property");
 }
 
 
@@ -941,6 +943,7 @@ _notmuch_message_add_filename (notmuch_message_t *message,
 {
     const char *relative, *directory;
     notmuch_status_t status;
+    notmuch_private_status_t private_status;
     void *local = talloc_new (message);
     char *direntry;
 
@@ -964,10 +967,17 @@ _notmuch_message_add_filename (notmuch_message_t *message,
 
     /* New file-direntry allows navigating to this message with
      * notmuch_directory_get_child_files() . */
-    status = COERCE_STATUS (_notmuch_message_add_term (message, "file-direntry", direntry),
-			    "adding file-direntry term");
-    if (status)
-	return status;
+    private_status = _notmuch_message_add_term (message, "file-direntry", direntry);
+    switch (private_status) {
+    case NOTMUCH_PRIVATE_STATUS_SUCCESS:
+	break;
+    case NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG:
+	_notmuch_database_log (message->notmuch, "filename too long for file-direntry term: %s\n",
+			       filename);
+	return NOTMUCH_STATUS_PATH_ERROR;
+    default:
+	return COERCE_STATUS (private_status, "adding file-direntry term");
+    }
 
     status = _notmuch_message_add_folder_terms (message, directory);
     if (status)
@@ -1383,21 +1393,22 @@ _notmuch_message_delete (notmuch_message_t *message)
     if (status)
 	return status;
 
-    message->notmuch->writable_xapian_db->delete_document (message->doc_id);
-
-    /* if this was a ghost to begin with, we are done */
-    private_status = _notmuch_message_has_term (message, "type", "ghost", &is_ghost);
-    if (private_status)
-	return COERCE_STATUS (private_status,
-			      "Error trying to determine whether message was a ghost");
-    if (is_ghost)
-	return NOTMUCH_STATUS_SUCCESS;
-
-    /* look for a non-ghost message in the same thread */
     try {
 	Xapian::PostingIterator thread_doc, thread_doc_end;
 	Xapian::PostingIterator mail_doc, mail_doc_end;
 
+	/* look for a non-ghost message in the same thread */
+	/* if this was a ghost to begin with, we are done */
+	private_status = _notmuch_message_has_term (message, "type", "ghost", &is_ghost);
+	if (private_status)
+	    return COERCE_STATUS (private_status,
+				  "Error trying to determine whether message was a ghost");
+
+	message->notmuch->writable_xapian_db->delete_document (message->doc_id);
+
+	if (is_ghost)
+	    return NOTMUCH_STATUS_SUCCESS;
+
 	_notmuch_database_find_doc_ids (message->notmuch, "thread", tid, &thread_doc,
 					&thread_doc_end);
 	_notmuch_database_find_doc_ids (message->notmuch, "type", "mail", &mail_doc, &mail_doc_end);
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 1d3d2b0c..c19ee8e2 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -259,6 +259,10 @@ _notmuch_database_filename_to_direntry (void *ctx,
 					notmuch_find_flags_t flags,
 					char **direntry);
 
+bool
+_notmuch_database_indexable_as_text (notmuch_database_t *notmuch,
+				     const char *mime_string);
+
 /* directory.cc */
 
 notmuch_directory_t *
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 0b0540b1..4e2b0fa4 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -293,6 +293,8 @@ typedef struct _notmuch_indexopts notmuch_indexopts_t;
  *
  * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory.
  *
+ * NOTMUCH_STATUS_PATH_ERROR: filename is too long
+ *
  * NOTMUCH_STATUS_FILE_ERROR: An error occurred trying to create the
  *	database file (such as permission denied, or file not found,
  *	etc.), or the database already exists.
@@ -720,7 +722,8 @@ notmuch_database_end_atomic (notmuch_database_t *notmuch);
  *
  * The UUID is a NUL-terminated opaque string that uniquely identifies
  * this database.  Two revision numbers are only comparable if they
- * have the same database UUID.
+ * have the same database UUID. The string 'uuid' is owned by notmuch
+ * and should not be freed or modified by the user.
  */
 unsigned long
 notmuch_database_get_revision (notmuch_database_t *notmuch,
@@ -1170,7 +1173,10 @@ notmuch_query_search_threads_st (notmuch_query_t *query, notmuch_threads_t **out
  *
  *     query = notmuch_query_create (database, query_string);
  *
- *     for (messages = notmuch_query_search_messages (query);
+ *     if (notmuch_query_search_messages (query, &messages) != NOTMUCH_STATUS_SUCCESS)
+ *         return EXIT_FAILURE;
+ *
+ *     for (;
  *          notmuch_messages_valid (messages);
  *          notmuch_messages_move_to_next (messages))
  *     {
@@ -2558,6 +2564,7 @@ typedef enum {
     NOTMUCH_CONFIG_USER_NAME,
     NOTMUCH_CONFIG_AUTOCOMMIT,
     NOTMUCH_CONFIG_EXTRA_HEADERS,
+    NOTMUCH_CONFIG_INDEX_AS_TEXT,
     NOTMUCH_CONFIG_LAST
 } notmuch_config_key_t;
 
diff --git a/lib/open.cc b/lib/open.cc
index 67ff868c..54d1faf3 100644
--- a/lib/open.cc
+++ b/lib/open.cc
@@ -320,6 +320,8 @@ _alloc_notmuch (const char *database_path, const char *config_path, const char *
     notmuch->transaction_count = 0;
     notmuch->transaction_threshold = 0;
     notmuch->view = 1;
+    notmuch->index_as_text = NULL;
+    notmuch->index_as_text_length = 0;
 
     notmuch->params = NOTMUCH_PARAM_NONE;
     if (database_path)
@@ -427,6 +429,53 @@ _load_database_state (notmuch_database_t *notmuch)
 	notmuch, notmuch->xapian_db->get_uuid ().c_str ());
 }
 
+/* XXX This should really be done lazily, but the error reporting path in the indexing code
+ * would need to be redone to report any errors.
+ */
+notmuch_status_t
+_ensure_index_as_text (notmuch_database_t *notmuch, char **message)
+{
+    int nregex = 0;
+    regex_t *regexv = NULL;
+
+    if (notmuch->index_as_text)
+	return NOTMUCH_STATUS_SUCCESS;
+
+    for (notmuch_config_values_t *list = notmuch_config_get_values (notmuch,
+								    NOTMUCH_CONFIG_INDEX_AS_TEXT);
+	 notmuch_config_values_valid (list);
+	 notmuch_config_values_move_to_next (list)) {
+	regex_t *new_regex;
+	int rerr;
+	const char *str = notmuch_config_values_get (list);
+	size_t len = strlen (str);
+
+	/* str must be non-empty, because n_c_get_values skips empty
+	 * strings */
+	assert (len > 0);
+
+	regexv = talloc_realloc (notmuch, regexv, regex_t, nregex + 1);
+	new_regex = &regexv[nregex];
+
+	rerr = regcomp (new_regex, str, REG_EXTENDED | REG_NOSUB);
+	if (rerr) {
+	    size_t error_size = regerror (rerr, new_regex, NULL, 0);
+	    char *error = (char *) talloc_size (str, error_size);
+
+	    regerror (rerr, new_regex, error, error_size);
+	    IGNORE_RESULT (asprintf (message, "Error in index.as_text: %s: %s\n", error, str));
+
+	    return NOTMUCH_STATUS_ILLEGAL_ARGUMENT;
+	}
+	nregex++;
+    }
+
+    notmuch->index_as_text = regexv;
+    notmuch->index_as_text_length = nregex;
+
+    return NOTMUCH_STATUS_SUCCESS;
+}
+
 static notmuch_status_t
 _finish_open (notmuch_database_t *notmuch,
 	      const char *profile,
@@ -531,6 +580,10 @@ _finish_open (notmuch_database_t *notmuch,
 	if (status)
 	    goto DONE;
 
+	status = _ensure_index_as_text (notmuch, &message);
+	if (status)
+	    goto DONE;
+
 	autocommit_str = notmuch_config_get (notmuch, NOTMUCH_CONFIG_AUTOCOMMIT);
 	if (unlikely (! autocommit_str)) {
 	    INTERNAL_ERROR ("missing configuration for autocommit");
diff --git a/lib/query.cc b/lib/query.cc
index 707f6222..1c60c122 100644
--- a/lib/query.cc
+++ b/lib/query.cc
@@ -20,6 +20,7 @@
 
 #include "notmuch-private.h"
 #include "database-private.h"
+#include "xapian-extra.h"
 
 #include <glib.h> /* GHashTable, GPtrArray */
 
@@ -186,7 +187,7 @@ _notmuch_query_string_to_xapian_query (notmuch_database_t *notmuch,
 {
     try {
 	if (query_string == "" || query_string == "*") {
-	    output = Xapian::Query::MatchAll;
+	    output = xapian_query_match_all ();
 	} else {
 	    output =
 		notmuch->query_parser->
diff --git a/lib/regexp-fields.cc b/lib/regexp-fields.cc
index 539915d8..3a775261 100644
--- a/lib/regexp-fields.cc
+++ b/lib/regexp-fields.cc
@@ -25,6 +25,7 @@
 #include "regexp-fields.h"
 #include "notmuch-private.h"
 #include "database-private.h"
+#include "xapian-extra.h"
 
 notmuch_status_t
 compile_regex (regex_t &regexp, const char *str, std::string &msg)
@@ -200,7 +201,7 @@ RegexpFieldProcessor::operator() (const std::string & str)
     if (str.empty ()) {
 	if (options & NOTMUCH_FIELD_PROBABILISTIC) {
 	    return Xapian::Query (Xapian::Query::OP_AND_NOT,
-				  Xapian::Query::MatchAll,
+				  xapian_query_match_all (),
 				  Xapian::Query (Xapian::Query::OP_WILDCARD, term_prefix));
 	} else {
 	    return Xapian::Query (term_prefix);
diff --git a/notmuch-client.h b/notmuch-client.h
index 21b49908..1a87240d 100644
--- a/notmuch-client.h
+++ b/notmuch-client.h
@@ -77,6 +77,8 @@ typedef struct notmuch_show_params {
     bool output_body;
     int duplicate;
     int part;
+    int offset;
+    int limit;
     _notmuch_crypto_t crypto;
     bool include_html;
     GMimeStream *out_stream;
diff --git a/notmuch-config.c b/notmuch-config.c
index e9456d79..8123e438 100644
--- a/notmuch-config.c
+++ b/notmuch-config.c
@@ -278,18 +278,24 @@ notmuch_conffile_open (notmuch_database_t *notmuch,
 	return NULL;
     }
 
-    if (config->is_new)
-	g_key_file_set_comment (config->key_file, NULL, NULL,
-				toplevel_config_comment, NULL);
-
     for (size_t i = 0; i < ARRAY_SIZE (group_comment_table); i++) {
 	const char *name = group_comment_table[i].group_name;
 	if (! g_key_file_has_group (config->key_file,  name)) {
 	    /* Force group to exist before adding comment */
 	    g_key_file_set_value (config->key_file, name, "dummy_key", "dummy_val");
 	    g_key_file_remove_key (config->key_file, name, "dummy_key", NULL);
-	    g_key_file_set_comment (config->key_file, name, NULL,
-				    group_comment_table[i].comment, NULL);
+	    if (config->is_new && (i == 0) ) {
+		const char *comment;
+
+		comment = talloc_asprintf (config, "%s\n%s",
+					   toplevel_config_comment,
+					   group_comment_table[i].comment);
+		g_key_file_set_comment (config->key_file, name, NULL, comment,
+					NULL);
+	    } else {
+		g_key_file_set_comment (config->key_file, name, NULL,
+					group_comment_table[i].comment, NULL);
+	    }
 	}
     }
     return config;
diff --git a/notmuch-git.py b/notmuch-git.py
index ceb86fbc..57098aae 100644
--- a/notmuch-git.py
+++ b/notmuch-git.py
@@ -254,7 +254,7 @@ def count_messages(prefix=None):
 def get_tags(prefix=None):
     "Get a list of tags with a given prefix."
     (status, stdout, stderr) = _spawn(
-        args=['notmuch', 'search', '--query=sexp', '--output=tags', _tag_query(prefix)],
+        args=['notmuch', 'search', '--exclude=false', '--query=sexp', '--output=tags', _tag_query(prefix)],
         stdout=_subprocess.PIPE, wait=True)
     return [tag for tag in stdout.splitlines()]
 
@@ -719,7 +719,7 @@ class DatabaseCache:
                 self._known[id] = False
         else:
             (_, stdout, stderr) = _spawn(
-                args=['notmuch', 'search', '--output=files', 'id:{0}'.format(id)],
+                args=['notmuch', 'search', '--exclude=false', '--output=files', 'id:{0}'.format(id)],
                 stdout=_subprocess.PIPE,
                 wait=True)
             self._known[id] = stdout != None
diff --git a/notmuch-new.c b/notmuch-new.c
index 346e6469..4a53e3eb 100644
--- a/notmuch-new.c
+++ b/notmuch-new.c
@@ -413,6 +413,10 @@ add_file (notmuch_database_t *notmuch, const char *filename,
     case NOTMUCH_STATUS_FILE_NOT_EMAIL:
 	fprintf (stderr, "Note: Ignoring non-mail file: %s\n", filename);
 	break;
+    case NOTMUCH_STATUS_PATH_ERROR:
+	fprintf (stderr, "Note: Ignoring non-indexable path: %s\n", filename);
+	(void) print_status_database ("add_file", notmuch, status);
+	break;
     case NOTMUCH_STATUS_FILE_ERROR:
 	/* Someone renamed/removed the file between scandir and now. */
 	state->vanished_files++;
diff --git a/notmuch-show.c b/notmuch-show.c
index ee9efa74..7fb40ce9 100644
--- a/notmuch-show.c
+++ b/notmuch-show.c
@@ -1159,6 +1159,18 @@ do_show_threaded (void *ctx,
     notmuch_thread_t *thread;
     notmuch_messages_t *messages;
     notmuch_status_t status, res = NOTMUCH_STATUS_SUCCESS;
+    int i;
+
+    if (params->offset < 0) {
+	unsigned count;
+	notmuch_status_t s = notmuch_query_count_threads (query, &count);
+	if (print_status_query ("notmuch show", query, s))
+	    return 1;
+
+	params->offset += count;
+	if (params->offset < 0)
+	    params->offset = 0;
+    }
 
     status = notmuch_query_search_threads (query, &threads);
     if (print_status_query ("notmuch show", query, status))
@@ -1166,11 +1178,16 @@ do_show_threaded (void *ctx,
 
     sp->begin_list (sp);
 
-    for (;
-	 notmuch_threads_valid (threads);
-	 notmuch_threads_move_to_next (threads)) {
+    for (i = 0;
+	 notmuch_threads_valid (threads) && (params->limit < 0 || i < params->offset + params->limit);
+	 notmuch_threads_move_to_next (threads), i++) {
 	thread = notmuch_threads_get (threads);
 
+	if (i < params->offset) {
+	    notmuch_thread_destroy (thread);
+	    continue;
+	}
+
 	messages = notmuch_thread_get_toplevel_messages (thread);
 
 	if (messages == NULL)
@@ -1201,6 +1218,18 @@ do_show_unthreaded (void *ctx,
     notmuch_message_t *message;
     notmuch_status_t status, res = NOTMUCH_STATUS_SUCCESS;
     notmuch_bool_t excluded;
+    int i;
+
+    if (params->offset < 0) {
+	unsigned count;
+	notmuch_status_t s = notmuch_query_count_messages (query, &count);
+	if (print_status_query ("notmuch show", query, s))
+	    return 1;
+
+	params->offset += count;
+	if (params->offset < 0)
+	    params->offset = 0;
+    }
 
     status = notmuch_query_search_messages (query, &messages);
     if (print_status_query ("notmuch show", query, status))
@@ -1208,9 +1237,13 @@ do_show_unthreaded (void *ctx,
 
     sp->begin_list (sp);
 
-    for (;
-	 notmuch_messages_valid (messages);
-	 notmuch_messages_move_to_next (messages)) {
+    for (i = 0;
+	 notmuch_messages_valid (messages) && (params->limit < 0 || i < params->offset + params->limit);
+	 notmuch_messages_move_to_next (messages), i++) {
+	if (i < params->offset) {
+	    continue;
+	}
+
 	sp->begin_list (sp);
 	sp->begin_list (sp);
 
@@ -1287,6 +1320,8 @@ notmuch_show_command (notmuch_database_t *notmuch, int argc, char *argv[])
     notmuch_show_params_t params = {
 	.part = -1,
 	.duplicate = 0,
+	.offset = 0,
+	.limit = -1, /* unlimited */
 	.omit_excluded = true,
 	.output_body = true,
 	.crypto = { .decrypt = NOTMUCH_DECRYPT_AUTO },
@@ -1328,6 +1363,8 @@ notmuch_show_command (notmuch_database_t *notmuch, int argc, char *argv[])
 	{ .opt_bool = &params.output_body, .name = "body" },
 	{ .opt_bool = &params.include_html, .name = "include-html" },
 	{ .opt_int = &params.duplicate, .name = "duplicate" },
+	{ .opt_int = &params.limit, .name = "limit" },
+	{ .opt_int = &params.offset, .name = "offset" },
 	{ .opt_inherit = notmuch_shared_options },
 	{ }
     };
diff --git a/performance-test/README b/performance-test/README
index 59b37b1b..1ca0df2f 100644
--- a/performance-test/README
+++ b/performance-test/README
@@ -24,11 +24,11 @@ Getting set up to run tests:
 First, you need to get the corpus.  If you don't already have the gpg
 key for David Bremner, run
 
-   % gpg --search 'david@tethera.net'
+   % gpg --locate-external-key 'david@tethera.net'
 
 This should get you a key with fingerprint
 
-    815B 6398 2A79 F8E7 C727  86C4 762B 57BB 7842 06AD
+    7A18 807F 100A 4570 C596  8420 7E4E 65C8 720B 706B
 
 (the last 8 digits are printed as the "key id").
 
diff --git a/performance-test/download/notmuch-email-corpus-0.5.tar.xz.asc b/performance-test/download/notmuch-email-corpus-0.5.tar.xz.asc
new file mode 100644
index 00000000..2318c2f6
--- /dev/null
+++ b/performance-test/download/notmuch-email-corpus-0.5.tar.xz.asc
@@ -0,0 +1,16 @@
+-----BEGIN PGP SIGNATURE-----
+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+=5/Ep
+-----END PGP SIGNATURE-----
diff --git a/performance-test/version.sh b/performance-test/version.sh
index f02527a7..357b9dad 100644
--- a/performance-test/version.sh
+++ b/performance-test/version.sh
@@ -1,3 +1,3 @@
 # this should be both a valid Makefile fragment and valid POSIX(ish) shell.
 
-PERFTEST_VERSION=0.4
+PERFTEST_VERSION=0.5
diff --git a/test/README b/test/README
index 10f127cb..a81808b1 100644
--- a/test/README
+++ b/test/README
@@ -137,6 +137,23 @@ detection of missing prerequisites. In the future we may treat tests
 unable to run because of missing prerequisites, but not explicitly
 skipped by the user, as failures.
 
+Testing installed notmuch
+-------------------------
+
+Systems integrators (e.g. Linux distros) may wish to test an installed
+version of notmuch.  This can be done be running
+
+     $ NOTMUCH_TEST_INSTALLED=1 ./test/notmuch-test
+
+In this scenario the test suite does not assume a built tree, and in
+particular cannot rely on the output of 'configure'. You may want to
+set certain feature environment variables ('NOTMUCH_HAVE_*') directly
+if you know those apply to your installed notmuch). Consider also
+setting TERM=dumb if the value of TERM cannot be used (e.g. in a
+chroot with missing terminfo). Note that having a built tree may cause
+surprising/broken results for NOTMUCH_TEST_INSTALLED, so consider
+cleaning first.
+
 Writing Tests
 -------------
 The test script is written as a shell script. It is to be named as
diff --git a/test/T000-basic.sh b/test/T000-basic.sh
index a2f4d93f..642f918d 100755
--- a/test/T000-basic.sh
+++ b/test/T000-basic.sh
@@ -66,6 +66,7 @@ test_begin_subtest 'NOTMUCH_CONFIG is set and points to an existing file'
 test_expect_success 'test -f "${NOTMUCH_CONFIG}"'
 
 test_begin_subtest 'PATH is set to build directory'
+test_subtest_broken_for_installed
 test_expect_equal \
     "$(dirname ${TEST_DIRECTORY})" \
     "$(echo $PATH|cut -f1 -d: | sed -e 's,/test/valgrind/bin$,,')"
diff --git a/test/T010-help-test.sh b/test/T010-help-test.sh
index da45d3ae..827edc14 100755
--- a/test/T010-help-test.sh
+++ b/test/T010-help-test.sh
@@ -12,13 +12,16 @@ test_expect_success 'notmuch help'
 test_begin_subtest 'notmuch --version'
 test_expect_success 'notmuch --version'
 
-if [ $NOTMUCH_HAVE_MAN -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_MAN-0}" = "1" ]; then
     test_begin_subtest 'notmuch --help tag'
     test_expect_success 'notmuch --help tag'
 
     test_begin_subtest 'notmuch help tag'
     test_expect_success 'notmuch help tag'
 else
+    if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+	test_done
+    fi
     test_begin_subtest 'notmuch --help tag (man pages not available)'
     test_expect_success 'test_must_fail notmuch --help tag >/dev/null'
 
diff --git a/test/T030-config.sh b/test/T030-config.sh
index 43bbce31..ea0b4012 100755
--- a/test/T030-config.sh
+++ b/test/T030-config.sh
@@ -57,6 +57,7 @@ database.mail_root=MAIL_DIR
 database.path=MAIL_DIR
 foo.list=this;is another;list value;
 foo.string=this is another string value
+index.as_text=
 maildir.synchronize_flags=true
 new.ignore=
 new.tags=unread;inbox
diff --git a/test/T040-setup.sh b/test/T040-setup.sh
index 10b29ec3..39846d34 100755
--- a/test/T040-setup.sh
+++ b/test/T040-setup.sh
@@ -21,7 +21,8 @@ baz
 EOF
 
 expected_dir=$NOTMUCH_SRCDIR/test/setup.expected-output
-test_expect_equal_file ${expected_dir}/config-with-comments new-notmuch-config
+sed '/^$/d' < new-notmuch-config > filtered-config
+test_expect_equal_file ${expected_dir}/config-with-comments filtered-config
 
 test_begin_subtest "setup consistent with config-set for single items"
 # note this relies on the config state from the previous test.
diff --git a/test/T050-new.sh b/test/T050-new.sh
index cb67889c..52888be2 100755
--- a/test/T050-new.sh
+++ b/test/T050-new.sh
@@ -383,7 +383,22 @@ No new mail. Removed 1 message.
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
+test_begin_subtest "Long file names have reasonable diagnostics"
+printf -v name 'f%.0s' {1..234}
+generate_message "[filename]=$name"
+notmuch new 2>&1 | notmuch_dir_sanitize >OUTPUT
+rm ${MAIL_DIR}/${name}
+cat <<EOF > EXPECTED
+Note: Ignoring non-indexable path: MAIL_DIR/$name
+add_file: Path supplied is illegal for this function
+filename too long for file-direntry term: MAIL_DIR/$name
+Processed 1 file in almost no time.
+No new mail.
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
 test_begin_subtest "Xapian exception: read only files"
+test_subtest_broken_for_root
 chmod u-w ${MAIL_DIR}/.notmuch/xapian/*.*
 output=$(NOTMUCH_NEW --debug 2>&1 | sed 's/: .*$//' )
 chmod u+w ${MAIL_DIR}/.notmuch/xapian/*.*
@@ -455,12 +470,4 @@ Date: Fri, 17 Jun 2016 22:14:41 -0400
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
-add_email_corpus indexing
-
-test_begin_subtest "index text/* attachments"
-test_subtest_known_broken
-notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain > EXPECTED
-notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain and ersatz > OUTPUT
-test_expect_equal_file_nonempty EXPECTED OUTPUT
-
 test_done
diff --git a/test/T055-path-config.sh b/test/T055-path-config.sh
index fe295324..efc79e8b 100755
--- a/test/T055-path-config.sh
+++ b/test/T055-path-config.sh
@@ -299,6 +299,7 @@ database.backup_dir
 database.hook_dir
 database.mail_root=MAIL_DIR
 database.path
+index.as_text=
 maildir.synchronize_flags=true
 new.ignore=
 new.tags=unread;inbox
diff --git a/test/T060-count.sh b/test/T060-count.sh
index 48146706..6e855b59 100755
--- a/test/T060-count.sh
+++ b/test/T060-count.sh
@@ -157,7 +157,7 @@ print("4: {} messages".format(query.count_messages()))
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_begin_subtest "and of exact terms (query=sexp)"
     output=$(notmuch count --query=sexp '(and "wonderful" "wizard")')
diff --git a/test/T080-search.sh b/test/T080-search.sh
index a3f0dead..515eb88f 100755
--- a/test/T080-search.sh
+++ b/test/T080-search.sh
@@ -34,6 +34,12 @@ add_message '[subject]="search by id"' '[date]="Sat, 01 Jan 2000 12:00:00 -0000"
 output=$(notmuch search id:${gen_msg_id} | notmuch_search_sanitize)
 test_expect_equal "$output" "thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; search by id (inbox unread)"
 
+test_begin_subtest "Message-Id with spaces"
+test_subtest_known_broken
+add_message '[id]="message id@example.com"' '[date]="Sat, 01 Jan 2000 12:00:00 -0000"'
+output=$(notmuch search --output=messages id:"message id@example.com")
+test_expect_equal "$output" "messageid@example.com"
+
 test_begin_subtest "Search by mid:"
 add_message '[subject]="search by mid"' '[date]="Sat, 01 Jan 2000 12:00:00 -0000"'
 output=$(notmuch search mid:${gen_msg_id} | notmuch_search_sanitize)
@@ -132,6 +138,7 @@ thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; search by to (inbox unread)
 thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; subjectsearchtest (inbox unread)
 thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; utf8-sübjéct (inbox unread)
 thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; search by id (inbox unread)
+thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; Message-Id with spaces (inbox unread)
 thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; search by mid (inbox unread)
 thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; search by tag (inbox searchbytag unread)
 thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; search by thread (inbox unread)
diff --git a/test/T081-sexpr-search.sh b/test/T081-sexpr-search.sh
index 0c7db9c2..8800b545 100755
--- a/test/T081-sexpr-search.sh
+++ b/test/T081-sexpr-search.sh
@@ -2,7 +2,7 @@
 test_description='"notmuch search" in several variations'
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_SFSEXP -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" != "1" ]; then
     printf "Skipping due to missing sfsexp library\n"
     test_done
 fi
diff --git a/test/T095-address.sh b/test/T095-address.sh
index 8bb3627a..0cafbe20 100755
--- a/test/T095-address.sh
+++ b/test/T095-address.sh
@@ -325,7 +325,7 @@ cat <<EOF >EXPECTED
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
-if [[ NOTMUCH_HAVE_SFSEXP = 1 ]]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
     test_begin_subtest "sexpr query: all messages"
     notmuch address '*' > EXPECTED
     notmuch address --query=sexp '()' > OUTPUT
diff --git a/test/T131-show-limiting.sh b/test/T131-show-limiting.sh
new file mode 100755
index 00000000..30d1f254
--- /dev/null
+++ b/test/T131-show-limiting.sh
@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+test_description='"notmuch show" --offset and --limit parameters'
+. $(dirname "$0")/test-lib.sh || exit 1
+
+add_email_corpus
+
+show () {
+    local kind="$1"
+    shift
+    if [ "$kind" = messages ]; then
+        set -- --unthreaded "$@"
+    fi
+    notmuch show --body=false --format=text --entire-thread=false "$@" "*" |
+        sed -nre 's/^.message\{.*\<depth:0\>.*/&/p'
+}
+
+for outp in messages threads; do
+    test_begin_subtest "$outp: limit does the right thing"
+    show $outp | head -n 20 >expected
+    show $outp --limit=20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: concatenation of limited shows"
+    show $outp | head -n 20 >expected
+    show $outp --limit=10 >output
+    show $outp --limit=10 --offset=10 >>output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: limit larger than result set"
+    N=$(notmuch count --output=$outp "*")
+    show $outp >expected
+    show $outp --limit=$((1 + N)) >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: limit = 0"
+    test_expect_equal "$(show $outp --limit=0)" ""
+
+    test_begin_subtest "$outp: offset does the right thing"
+    # note: tail -n +N is 1-based
+    show $outp | tail -n +21 >expected
+    show $outp --offset=20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: offset = 0"
+    show $outp >expected
+    show $outp --offset=0 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset"
+    show $outp | tail -n 20 >expected
+    show $outp --offset=-20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset"
+    show $outp | tail -n 1 >expected
+    show $outp --offset=-1 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset combined with limit"
+    show $outp | tail -n 20 | head -n 10 >expected
+    show $outp --offset=-20 --limit=10 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset combined with equal limit"
+    show $outp | tail -n 20 >expected
+    show $outp --offset=-20 --limit=20 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset combined with large limit"
+    show $outp | tail -n 20 >expected
+    show $outp --offset=-20 --limit=50 >output
+    test_expect_equal_file expected output
+
+    test_begin_subtest "$outp: negative offset larger than results"
+    N=$(notmuch count --output=$outp "*")
+    show $outp >expected
+    show $outp --offset=-$((1 + N)) >output
+    test_expect_equal_file expected output
+done
+
+test_done
diff --git a/test/T150-tagging.sh b/test/T150-tagging.sh
index 1a2fd77e..273c0af3 100755
--- a/test/T150-tagging.sh
+++ b/test/T150-tagging.sh
@@ -320,6 +320,7 @@ test_begin_subtest "Tag name beginning with -"
 test_expect_code 1 'notmuch tag +- One'
 
 test_begin_subtest "Xapian exception: read only files"
+test_subtest_broken_for_root
 chmod u-w ${MAIL_DIR}/.notmuch/xapian/*.*
 output=$(notmuch tag +something '*' 2>&1 | sed 's/: .*$//' )
 chmod u+w ${MAIL_DIR}/.notmuch/xapian/*.*
@@ -327,7 +328,7 @@ test_expect_equal "$output" "A Xapian exception occurred opening database"
 
 add_email_corpus
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_query_syntax '(and "wonderful" "wizard")' 'wonderful and wizard'
     test_query_syntax '(or "php" "wizard")' 'php or wizard'
diff --git a/test/T160-json.sh b/test/T160-json.sh
index 4a797f6a..318c9788 100755
--- a/test/T160-json.sh
+++ b/test/T160-json.sh
@@ -65,8 +65,9 @@ test_expect_equal_json "$output" "[{\"thread\": \"XXX\",
  \"tags\": [\"inbox\",
  \"unread\"]}]"
 
+if [ -z "${NOTMUCH_TEST_INSTALLED-}" ]; then
 test_begin_subtest "Search message: json, 64-bit timestamp"
-if [ $NOTMUCH_HAVE_64BIT_TIME_T -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_64BIT_TIME_T-0}" != "1" ]; then
     test_subtest_known_broken
 fi
 add_message "[subject]=\"json-search-64bit-timestamp-subject\"" "[date]=\"Tue, 01 Jan 2999 12:00:00 -0000\"" "[body]=\"json-search-64bit-timestamp-message\""
@@ -81,6 +82,7 @@ test_expect_equal_json "$output" "[{\"thread\": \"XXX\",
  \"query\": [\"id:$gen_msg_id\", null],
  \"tags\": [\"inbox\",
  \"unread\"]}]"
+fi # NOTMUCH_TEST_INSTALLED undefined / empty
 
 test_begin_subtest "Format version: too low"
 test_expect_code 20 "notmuch search --format-version=0 \\*"
diff --git a/test/T220-reply.sh b/test/T220-reply.sh
index 207f5788..120d7138 100755
--- a/test/T220-reply.sh
+++ b/test/T220-reply.sh
@@ -24,7 +24,7 @@ test_begin_subtest "Basic reply"
 notmuch reply id:${gen_msg_id} >OUTPUT 2>&1 && echo OK >> OUTPUT
 test_expect_equal_file basic.expected OUTPUT
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_begin_subtest "Basic reply (query=sexp)"
     notmuch reply --query=sexp "(id ${gen_msg_id})" >OUTPUT 2>&1 && echo OK >> OUTPUT
diff --git a/test/T240-dump-restore.sh b/test/T240-dump-restore.sh
index a86f0fb7..c3f18839 100755
--- a/test/T240-dump-restore.sh
+++ b/test/T240-dump-restore.sh
@@ -118,7 +118,7 @@ notmuch dump -- from:cworth > dump-dash-cworth.actual
 test_expect_equal_file dump-cworth.expected dump-dash-cworth.actual
 
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_begin_subtest "dump --query=sexp -- '(from cworth)'"
     notmuch dump --query=sexp -- '(from cworth)' > dump-dash-cworth.actual2
@@ -139,6 +139,7 @@ notmuch dump --output=dump-outfile-dash-inbox.actual -- from:cworth
 test_expect_equal_file dump-cworth.expected dump-outfile-dash-inbox.actual
 
 test_begin_subtest "Check for a safe set of message-ids"
+test_subtest_broken_for_installed
 notmuch search --output=messages from:cworth | sed s/^id:// > EXPECTED
 notmuch search --output=messages from:cworth | sed s/^id:// |\
 	$TEST_DIRECTORY/hex-xcode --direction=encode > OUTPUT
@@ -246,6 +247,7 @@ notmuch dump --format=batch-tag > OUTPUT.$test_count
 test_expect_equal_file EXPECTED.$test_count OUTPUT.$test_count
 
 test_begin_subtest 'format=batch-tag, checking encoded output'
+test_subtest_broken_for_installed
 NOTMUCH_DUMP_TAGS --format=batch-tag -- from:cworth |\
 	 awk "{ print \"+$enc1 +$enc2 +$enc3 -- \" \$5 }" > EXPECTED.$test_count
 NOTMUCH_DUMP_TAGS --format=batch-tag -- from:cworth > OUTPUT.$test_count
diff --git a/test/T310-emacs.sh b/test/T310-emacs.sh
index 9d0df187..d3aa2e7d 100755
--- a/test/T310-emacs.sh
+++ b/test/T310-emacs.sh
@@ -258,6 +258,7 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "Verify that sent messages are saved/searchable (via FCC)"
+test_subtest_broken_for_installed
 notmuch new > /dev/null
 output=$(notmuch search 'subject:"testing message sent via SMTP"' | notmuch_search_sanitize)
 test_expect_equal "$output" "thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; Testing message sent via SMTP (inbox)"
@@ -350,6 +351,7 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "Reply within emacs"
+test_subtest_broken_for_installed
 test_emacs '(let ((message-hidden-headers ''()))
 	    (notmuch-search "subject:\"testing message sent via SMTP\"")
 	    (notmuch-test-wait)
diff --git a/test/T350-crypto.sh b/test/T350-crypto.sh
index 721cbfdd..27c0e86d 100755
--- a/test/T350-crypto.sh
+++ b/test/T350-crypto.sh
@@ -30,6 +30,7 @@ msg_file=$(notmuch search --output=files subject:signed-message-sent-via-SMTP)
 test_expect_equal_message_body sent_message "$msg_file"
 
 test_begin_subtest "signed part content-type indexing"
+test_subtest_broken_for_installed
 notmuch search mimetype:multipart/signed and mimetype:application/pgp-signature | notmuch_search_sanitize > OUTPUT
 cat <<EOF >EXPECTED
 thread:XXX   2000-01-01 [1/1] Notmuch Test Suite; test signed message 001 (inbox signed)
diff --git a/test/T355-smime.sh b/test/T355-smime.sh
index 809274ce..d2118c04 100755
--- a/test/T355-smime.sh
+++ b/test/T355-smime.sh
@@ -183,8 +183,9 @@ test_begin_subtest "show PKCS#7 SignedData outputs valid JSON"
 output=$(notmuch show --format=json id:smime-onepart-signed@protected-headers.example)
 test_valid_json "$output"
 
+if [ -z "${NOTMUCH_TEST_INSTALLED-}" ]; then
 test_begin_subtest "Verify signature on PKCS#7 SignedData message"
-if [ $NOTMUCH_HAVE_64BIT_TIME_T -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_64BIT_TIME_T-0}" != "1" ]; then
     test_subtest_known_broken
 fi
 output=$(notmuch show --format=json id:smime-onepart-signed@protected-headers.example)
@@ -194,6 +195,7 @@ test_json_nodes <<<"$output" \
                 'expires:[0][0][0]["crypto"]["signed"]["status"][0]["expires"]=2611032858' \
                 'fingerprint:[0][0][0]["crypto"]["signed"]["status"][0]["fingerprint"]="702BA4B157F1E2B7D16B0C6A5FFC8A7DE2057DEB"' \
                 'status:[0][0][0]["crypto"]["signed"]["status"][0]["status"]="good"'
+fi # NOTMUCH_TEST_INSTALLED undefined / empty
 
 test_begin_subtest "Verify signature on PKCS#7 SignedData message signer User ID"
 if [ $NOTMUCH_GMIME_X509_CERT_VALIDITY -ne 1 ]; then
diff --git a/test/T360-symbol-hiding.sh b/test/T360-symbol-hiding.sh
index 642457bf..ff06ff69 100755
--- a/test/T360-symbol-hiding.sh
+++ b/test/T360-symbol-hiding.sh
@@ -11,6 +11,10 @@ test_description='exception symbol hiding'
 
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 test_begin_subtest 'running test' run_test
 mkdir -p ${PWD}/fakedb/.notmuch
 $TEST_DIRECTORY/symbol-test ${PWD}/fakedb ${PWD}/nonexistent 2>&1 \
diff --git a/test/T390-python.sh b/test/T390-python.sh
index 9f71ce3c..21912431 100755
--- a/test/T390-python.sh
+++ b/test/T390-python.sh
@@ -4,6 +4,10 @@ test_description="python bindings"
 
 test_require_external_prereq ${NOTMUCH_PYTHON}
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 add_email_corpus
 add_gnupg_home
 
diff --git a/test/T391-python-cffi.sh b/test/T391-python-cffi.sh
index 30872af0..0059b050 100755
--- a/test/T391-python-cffi.sh
+++ b/test/T391-python-cffi.sh
@@ -2,10 +2,13 @@
 test_description="python bindings (pytest)"
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_PYTHON3_CFFI -eq 0 -o $NOTMUCH_HAVE_PYTHON3_PYTEST -eq 0 ]; then
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
     test_done
 fi
 
+if [ "${NOTMUCH_HAVE_PYTHON3_CFFI-0}" = "0" -o "${NOTMUCH_HAVE_PYTHON3_PYTEST-0}" = "0" ]; then
+    test_done
+fi
 
 test_begin_subtest "python cffi tests (NOTMUCH_CONFIG set)"
 pytest_dir=$NOTMUCH_BUILDDIR/bindings/python-cffi/build/stage
diff --git a/test/T392-python-cffi-notmuch.sh b/test/T392-python-cffi-notmuch.sh
index 15c8fc6b..06161219 100755
--- a/test/T392-python-cffi-notmuch.sh
+++ b/test/T392-python-cffi-notmuch.sh
@@ -2,7 +2,7 @@
 test_description="python bindings (notmuch test suite)"
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_PYTHON3_CFFI -eq 0 -o $NOTMUCH_HAVE_PYTHON3_PYTEST -eq 0 ]; then
+if [ "${NOTMUCH_HAVE_PYTHON3_CFFI-0}" = "0" -o "${NOTMUCH_HAVE_PYTHON3_PYTEST-0}" = "0" ]; then
     test_done
 fi
 
diff --git a/test/T395-ruby.sh b/test/T395-ruby.sh
index e828efed..d0c6bb17 100755
--- a/test/T395-ruby.sh
+++ b/test/T395-ruby.sh
@@ -2,7 +2,7 @@
 test_description="ruby bindings"
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ "${NOTMUCH_HAVE_RUBY_DEV}" = "0" ]; then
+if [ -z "${NOTMUCH_TEST_INSTALLED-}" -a "${NOTMUCH_HAVE_RUBY_DEV-0}" = "0" ]; then
     test_subtest_missing_external_prereq_["ruby development files"]=t
 fi
 
@@ -12,10 +12,14 @@ test_ruby() {
     (
 	cat <<-EOF
 	require 'notmuch'
-	db = Notmuch::Database.new('$MAIL_DIR')
+	db = Notmuch::Database.new()
 	EOF
 	cat
-    ) | $NOTMUCH_RUBY -I "$NOTMUCH_BUILDDIR/bindings/ruby"> OUTPUT
+    ) | if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+	ruby
+    else
+	$NOTMUCH_RUBY -I "$NOTMUCH_BUILDDIR/bindings/ruby"
+    fi> OUTPUT
     test_expect_equal_file EXPECTED OUTPUT
 }
 
diff --git a/test/T410-argument-parsing.sh b/test/T410-argument-parsing.sh
index d9aa8e2d..40b625fe 100755
--- a/test/T410-argument-parsing.sh
+++ b/test/T410-argument-parsing.sh
@@ -2,6 +2,10 @@
 test_description="argument parsing"
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 test_begin_subtest "sanity check"
 $TEST_DIRECTORY/arg-test pos1 --keyword=one --boolean --string=foo pos2 --int=7 --flag=one --flag=three > OUTPUT
 cat <<EOF > EXPECTED
diff --git a/test/T460-emacs-tree.sh b/test/T460-emacs-tree.sh
index 3a1c449e..8e071443 100755
--- a/test/T460-emacs-tree.sh
+++ b/test/T460-emacs-tree.sh
@@ -200,6 +200,30 @@ test_emacs '(test-log-error
 	        (notmuch-tree "*")))'
 test_expect_equal "$(cat MESSAGES)" "COMPLETE"
 
+# reinitialize database for outline tests
+add_email_corpus
+
+test_begin_subtest "start in outline mode"
+test_emacs '(let ((notmuch-tree-outline-enabled t))
+	(notmuch-tree "tag:inbox")
+	(notmuch-test-wait)
+	(test-visible-output))'
+# folding all messages by height or depth should look the same
+test_expect_equal_file $EXPECTED/inbox-outline OUTPUT
+
+test_begin_subtest "outline-cycle-buffer"
+test_emacs '(let ((notmuch-tree-outline-enabled t))
+	(notmuch-tree "tag:inbox")
+	(notmuch-test-wait)
+	(outline-cycle-buffer)
+	(outline-cycle-buffer)
+	(notmuch-test-wait)
+	(test-visible-output))'
+# folding all messages by height or depth should look the same
+test_expect_equal_file $EXPECTED/notmuch-tree-tag-inbox OUTPUT
+
+test_done
+
 add_email_corpus duplicate
 
 ID3=87r2ecrr6x.fsf@zephyr.silentflame.com
diff --git a/test/T480-hex-escaping.sh b/test/T480-hex-escaping.sh
index b2eb80b9..8bddf3e7 100755
--- a/test/T480-hex-escaping.sh
+++ b/test/T480-hex-escaping.sh
@@ -2,6 +2,10 @@
 test_description="hex encoding and decoding"
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 test_begin_subtest "round trip"
 find $NOTMUCH_SRCDIR/test/corpora/default -type f -print | sort | xargs cat > EXPECTED
 $TEST_DIRECTORY/hex-xcode --direction=encode < EXPECTED | $TEST_DIRECTORY/hex-xcode --direction=decode > OUTPUT
diff --git a/test/T490-parse-time-string.sh b/test/T490-parse-time-string.sh
index f89755ed..3b6e48c4 100755
--- a/test/T490-parse-time-string.sh
+++ b/test/T490-parse-time-string.sh
@@ -2,6 +2,10 @@
 test_description="date/time parser module"
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 # Sanity/smoke tests for the date/time parser independent of notmuch
 
 _date () {
diff --git a/test/T520-show.sh b/test/T520-show.sh
index c7b73a6d..6bcf109c 100755
--- a/test/T520-show.sh
+++ b/test/T520-show.sh
@@ -35,7 +35,7 @@ notmuch show --entire-thread=true --sort=oldest-first $QUERY > OUTPUT
 test_expect_equal_file EXPECTED OUTPUT
 
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     test_query_syntax '(and "wonderful" "wizard")' 'wonderful and wizard'
     test_query_syntax '(or "php" "wizard")' 'php or wizard'
diff --git a/test/T550-db-features.sh b/test/T550-db-features.sh
index 9d5a9e70..3048c7c4 100755
--- a/test/T550-db-features.sh
+++ b/test/T550-db-features.sh
@@ -3,6 +3,10 @@ test_description="database version and feature compatibility"
 
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 test_begin_subtest "future database versions abort open"
 ${TEST_DIRECTORY}/make-db-version ${MAIL_DIR} 9999 ""
 output=$(notmuch search x 2>&1 | sed 's/\(database at\) .*/\1 FILENAME/')
diff --git a/test/T566-lib-message.sh b/test/T566-lib-message.sh
index 511d56ca..69051937 100755
--- a/test/T566-lib-message.sh
+++ b/test/T566-lib-message.sh
@@ -3,6 +3,10 @@ test_description="API tests for notmuch_message_*"
 
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED}" ]; then
+    test_done
+fi
+
 add_email_corpus
 
 test_begin_subtest "building database"
@@ -516,4 +520,31 @@ cat <<EOF > EXPECTED
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
+TERMLIST_PATH=(${MAIL_DIR}/.notmuch/xapian/termlist.*)
+test_begin_subtest "remove message with corrupted db"
+backup_database
+cat c_head0 - c_tail <<'EOF' | test_private_C ${MAIL_DIR} ${TERMLIST_PATH}
+    {
+        notmuch_status_t status;
+
+        int fd = open(argv[2],O_WRONLY|O_TRUNC);
+        if (fd < 0) {
+            fprintf (stderr, "error opening %s\n", argv[1]);
+            exit (1);
+        }
+
+        stat = _notmuch_message_delete (message);
+        printf ("%d\n", stat == NOTMUCH_STATUS_XAPIAN_EXCEPTION);
+    }
+EOF
+cat <<EOF > EXPECTED
+== stdout ==
+1
+== stderr ==
+A Xapian exception occurred at message.cc:XXX: EOF reading block YYY
+EOF
+sed 's/EOF reading block [0-9]*/EOF reading block YYY/' < OUTPUT > OUTPUT.clean
+test_expect_equal_file EXPECTED OUTPUT.clean
+restore_database
+
 test_done
diff --git a/test/T570-revision-tracking.sh b/test/T570-revision-tracking.sh
index a7480050..bcc97dd9 100755
--- a/test/T570-revision-tracking.sh
+++ b/test/T570-revision-tracking.sh
@@ -95,7 +95,7 @@ subtotal=$(notmuch count lastmod:..$lastmod)
 result=$(($subtotal == $total-1))
 test_expect_equal 1 "$result"
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
     test_begin_subtest 'exclude one message using negative lastmod (sexp)'
     total=$(notmuch count '*')
     notmuch tag +${RANDOM} id:4EFC743A.3060609@april.org
diff --git a/test/T590-libconfig.sh b/test/T590-libconfig.sh
index 26a1f033..9326ba3e 100755
--- a/test/T590-libconfig.sh
+++ b/test/T590-libconfig.sh
@@ -440,6 +440,7 @@ cat <<'EOF' >EXPECTED
 10: 'USER_FULL_NAME'
 11: '8000'
 12: 'NULL'
+13: ''
 == stderr ==
 EOF
 unset MAILDIR
@@ -725,6 +726,7 @@ test_expect_equal_file EXPECTED OUTPUT
 test_begin_subtest "list by keys (ndlc)"
 notmuch config set search.exclude_tags "foo;bar;fub"
 notmuch config set new.ignore "sekrit_junk"
+notmuch config set index.as_text "text/"
 cat c_head2 - c_tail <<'EOF' | test_C ${MAIL_DIR} %NULL% %NULL%
 {
     notmuch_config_key_t key;
@@ -751,6 +753,7 @@ cat <<'EOF' >EXPECTED
 10: 'Notmuch Test Suite'
 11: '8000'
 12: 'NULL'
+13: 'text/'
 == stderr ==
 EOF
 test_expect_equal_file EXPECTED OUTPUT
@@ -785,6 +788,7 @@ cat <<'EOF' >EXPECTED
 10: 'USER_FULL_NAME'
 11: '8000'
 12: 'NULL'
+13: ''
 == stderr ==
 EOF
 test_expect_equal_file EXPECTED OUTPUT.clean
@@ -856,6 +860,7 @@ database.backup_dir MAIL_DIR/.notmuch/backups
 database.hook_dir MAIL_DIR/.notmuch/hooks
 database.mail_root MAIL_DIR
 database.path MAIL_DIR
+index.as_text text/
 key with spaces value, with, spaces!
 maildir.synchronize_flags true
 new.ignore sekrit_junk
diff --git a/test/T592-thread-breakage.sh b/test/T592-thread-breakage.sh
index 92a70e3e..2334fcaf 100755
--- a/test/T592-thread-breakage.sh
+++ b/test/T592-thread-breakage.sh
@@ -21,6 +21,10 @@ test_description='thread breakage during reindexing'
 
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 message_a () {
     mkdir -p ${MAIL_DIR}/cur
     cat > ${MAIL_DIR}/cur/a <<EOF
diff --git a/test/T610-message-property.sh b/test/T610-message-property.sh
index 2685f3b5..a7cbe048 100755
--- a/test/T610-message-property.sh
+++ b/test/T610-message-property.sh
@@ -12,7 +12,7 @@ void print_properties (notmuch_message_t *message, const char *prefix, notmuch_b
     notmuch_message_properties_t *list;
     for (list = notmuch_message_get_properties (message, prefix, exact);
          notmuch_message_properties_valid (list); notmuch_message_properties_move_to_next (list)) {
-       printf("%s\n", notmuch_message_properties_value(list));
+       printf("%s = %s\n", notmuch_message_properties_key(list), notmuch_message_properties_value(list));
     }
     notmuch_message_properties_destroy (list);
 }
@@ -89,17 +89,6 @@ testkey2 = NULL
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
-test_begin_subtest "notmuch_message_remove_all_properties"
-cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
-EXPECT0(notmuch_message_remove_all_properties (message, NULL));
-print_properties (message, "", FALSE);
-EOF
-cat <<'EOF' >EXPECTED
-== stdout ==
-== stderr ==
-EOF
-test_expect_equal_file EXPECTED OUTPUT
-
 test_begin_subtest "testing string map binary search (via message properties)"
 cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
 {
@@ -157,7 +146,28 @@ print_properties (message, "testkey1", TRUE);
 EOF
 cat <<'EOF' >EXPECTED
 == stdout ==
-testvalue1
+testkey1 = testvalue1
+== stderr ==
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "notmuch_message_remove_all_properties"
+cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
+EXPECT0(notmuch_message_remove_all_properties (message, NULL));
+EXPECT0(notmuch_database_destroy(db));
+EXPECT0(notmuch_database_open_with_config (argv[1],
+                                           NOTMUCH_DATABASE_MODE_READ_WRITE,
+                                           "", NULL, &db, &msg));
+if (msg) fputs (msg, stderr);
+EXPECT0(notmuch_database_find_message(db, "4EFC743A.3060609@april.org", &message));
+if (message == NULL) {
+  fprintf (stderr, "unable to find message");
+  exit (1);
+}
+print_properties (message, "", FALSE);
+EOF
+cat <<'EOF' >EXPECTED
+== stdout ==
 == stderr ==
 EOF
 test_expect_equal_file EXPECTED OUTPUT
@@ -171,10 +181,9 @@ print_properties (message, "testkey1", TRUE);
 EOF
 cat <<'EOF' >EXPECTED
 == stdout ==
-alice
-bob
-testvalue1
-testvalue2
+testkey1 = alice
+testkey1 = bob
+testkey1 = testvalue2
 == stderr ==
 EOF
 test_expect_equal_file EXPECTED OUTPUT
@@ -186,27 +195,14 @@ EXPECT0(notmuch_message_add_property (message, "testkey3", "testvalue3"));
 EXPECT0(notmuch_message_add_property (message, "testkey3", "alice3"));
 print_properties (message, "testkey", FALSE);
 EOF
-# expected: 4 values for testkey1, 3 values for testkey3
-# they are not guaranteed to be sorted, so sort them, leaving the first
-# line '== stdout ==' and the end ('== stderr ==' and whatever error
-# may have been printed) alone
-mv OUTPUT unsorted_OUTPUT
-awk ' NR == 1 { print; next } \
-      NR < 6  { print | "sort"; next } \
-      NR == 6 { close("sort") } \
-      NR < 9  { print | "sort"; next } \
-      NR == 9 { close("sort") } \
-      { print }' unsorted_OUTPUT > OUTPUT
-rm unsorted_OUTPUT
 cat <<'EOF' >EXPECTED
 == stdout ==
-alice
-bob
-testvalue1
-testvalue2
-alice3
-bob3
-testvalue3
+testkey1 = alice
+testkey1 = bob
+testkey1 = testvalue2
+testkey3 = alice3
+testkey3 = bob3
+testkey3 = testvalue3
 == stderr ==
 EOF
 test_expect_equal_file EXPECTED OUTPUT
@@ -248,7 +244,7 @@ test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "dump message properties"
 cat <<EOF > PROPERTIES
-#= 4EFC743A.3060609@april.org fancy%20key%20with%20%c3%a1cc%c3%a8nts=import%20value%20with%20= testkey1=alice testkey1=bob testkey1=testvalue1 testkey1=testvalue2 testkey3=alice3 testkey3=bob3 testkey3=testvalue3
+#= 4EFC743A.3060609@april.org fancy%20key%20with%20%c3%a1cc%c3%a8nts=import%20value%20with%20= testkey1=alice testkey1=bob testkey1=testvalue2 testkey3=alice3 testkey3=bob3 testkey3=testvalue3
 EOF
 cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
 EXPECT0(notmuch_message_add_property (message, "fancy key with áccènts", "import value with ="));
@@ -259,7 +255,7 @@ test_expect_equal_file PROPERTIES OUTPUT
 test_begin_subtest "dump _only_ message properties"
 cat <<EOF > EXPECTED
 #notmuch-dump batch-tag:3 properties
-#= 4EFC743A.3060609@april.org fancy%20key%20with%20%c3%a1cc%c3%a8nts=import%20value%20with%20= testkey1=alice testkey1=bob testkey1=testvalue1 testkey1=testvalue2 testkey3=alice3 testkey3=bob3 testkey3=testvalue3
+#= 4EFC743A.3060609@april.org fancy%20key%20with%20%c3%a1cc%c3%a8nts=import%20value%20with%20= testkey1=alice testkey1=bob testkey1=testvalue2 testkey3=alice3 testkey3=bob3 testkey3=testvalue3
 EOF
 notmuch dump --include=properties > OUTPUT
 test_expect_equal_file EXPECTED OUTPUT
@@ -328,7 +324,6 @@ EOF
 cat <<'EOF' > EXPECTED
 testkey1 = alice
 testkey1 = bob
-testkey1 = testvalue1
 testkey1 = testvalue2
 EOF
 test_expect_equal_file EXPECTED OUTPUT
@@ -344,7 +339,6 @@ EOF
 cat <<'EOF' > EXPECTED
 testkey1 = alice
 testkey1 = bob
-testkey1 = testvalue1
 testkey1 = testvalue2
 testkey3 = alice3
 testkey3 = bob3
@@ -362,4 +356,49 @@ for (key,val) in msg.get_properties("testkey",True):
 EOF
 test_expect_equal_file /dev/null OUTPUT
 
+test_begin_subtest "notmuch_message_remove_all_properties_with_prefix"
+cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
+EXPECT0(notmuch_message_remove_all_properties_with_prefix (message, "testkey3"));
+print_properties (message, "", FALSE);
+EOF
+cat <<'EOF' >EXPECTED
+== stdout ==
+fancy key with áccènts = import value with =
+testkey1 = alice
+testkey1 = bob
+testkey1 = testvalue2
+== stderr ==
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "edit property on removed message without uncaught exception"
+cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
+EXPECT0(notmuch_database_remove_message (db, notmuch_message_get_filename (message)));
+stat = notmuch_message_remove_property (message, "example", "example");
+if (stat == NOTMUCH_STATUS_XAPIAN_EXCEPTION)
+    fprintf (stderr, "unable to remove properties on message");
+EOF
+cat <<'EOF' >EXPECTED
+== stdout ==
+== stderr ==
+unable to remove properties on message
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+add_email_corpus
+
+test_begin_subtest "remove all properties on removed message without uncaught exception"
+cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
+EXPECT0(notmuch_database_remove_message (db, notmuch_message_get_filename (message)));
+stat = notmuch_message_remove_all_properties_with_prefix (message, "");
+if (stat == NOTMUCH_STATUS_XAPIAN_EXCEPTION)
+    fprintf (stderr, "unable to remove properties on message");
+EOF
+cat <<'EOF' >EXPECTED
+== stdout ==
+== stderr ==
+unable to remove properties on message
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
 test_done
diff --git a/test/T700-reindex.sh b/test/T700-reindex.sh
index 347f8483..af34ad7c 100755
--- a/test/T700-reindex.sh
+++ b/test/T700-reindex.sh
@@ -5,7 +5,7 @@ test_description='reindexing messages'
 add_email_corpus
 
 
-if [ $NOTMUCH_HAVE_SFSEXP -eq 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" = "1" ]; then
 
     count=$(notmuch count --lastmod '*' | cut -f 3)
     for query in '()' '(not)' '(and)' '(or ())' '(or (not))' '(or (and))' \
diff --git a/test/T710-message-id.sh b/test/T710-message-id.sh
index 5129d84c..a2d8ec71 100755
--- a/test/T710-message-id.sh
+++ b/test/T710-message-id.sh
@@ -3,6 +3,10 @@ test_description="message id parsing"
 
 . $(dirname "$0")/test-lib.sh || exit 1
 
+if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    test_done
+fi
+
 test_begin_subtest "good message ids"
 ${TEST_DIRECTORY}/message-id-parse <<EOF >OUTPUT
 <018b1a8f2d1df62e804ce88b65401304832dfbbf.1346614915.git.jani@nikula.org>
diff --git a/test/T760-as-text.sh b/test/T760-as-text.sh
new file mode 100755
index 00000000..744567f2
--- /dev/null
+++ b/test/T760-as-text.sh
@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+test_description='index attachments as text'
+. $(dirname "$0")/test-lib.sh || exit 1
+
+add_email_corpus indexing
+test_begin_subtest "empty as_text; skip text/x-diff"
+messages=$(notmuch count id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain)
+count=$(notmuch count id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain and ersatz)
+test_expect_equal "$messages,$count" "1,0"
+
+notmuch config set index.as_text "^text/"
+add_email_corpus indexing
+
+test_begin_subtest "as_index is text/; find text/x-diff"
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain > EXPECTED
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain and ersatz > OUTPUT
+test_expect_equal_file_nonempty EXPECTED OUTPUT
+
+test_begin_subtest "reindex with empty as_text, skips text/x-diff"
+notmuch config set index.as_text
+notmuch reindex '*'
+messages=$(notmuch count id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain)
+count=$(notmuch count id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain and ersatz)
+test_expect_equal "$messages,$count" "1,0"
+
+test_begin_subtest "reindex with empty as_text; skips application/pdf"
+notmuch config set index.as_text
+notmuch reindex '*'
+gmessages=$(notmuch count id:871qo9p4tf.fsf@tethera.net)
+count=$(notmuch count id:871qo9p4tf.fsf@tethera.net and body:not-really-PDF)
+test_expect_equal "$messages,$count" "1,0"
+
+test_begin_subtest "reindex with as_text as text/; finds text/x-diff"
+notmuch config set index.as_text "^text/"
+notmuch reindex '*'
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain > EXPECTED
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain and ersatz > OUTPUT
+test_expect_equal_file_nonempty EXPECTED OUTPUT
+
+test_begin_subtest "reindex with as_text as text/; skips application/pdf"
+notmuch config set index.as_text "^text/"
+notmuch config set index.as_text
+notmuch reindex '*'
+messages=$(notmuch count id:871qo9p4tf.fsf@tethera.net)
+count=$(notmuch count id:871qo9p4tf.fsf@tethera.net and body:not-really-PDF)
+test_expect_equal "$messages,$count" "1,0"
+
+test_begin_subtest "as_text has multiple regexes"
+notmuch config set index.as_text "blahblah;^text/"
+notmuch reindex '*'
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain > EXPECTED
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain and ersatz > OUTPUT
+test_expect_equal_file_nonempty EXPECTED OUTPUT
+
+test_begin_subtest "as_text is non-anchored regex"
+notmuch config set index.as_text "e.t/"
+notmuch reindex '*'
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain > EXPECTED
+notmuch search id:20200930101213.2m2pt3jrspvcrxfx@localhost.localdomain and ersatz > OUTPUT
+test_expect_equal_file_nonempty EXPECTED OUTPUT
+
+test_begin_subtest "as_text is 'application/pdf'"
+notmuch config set index.as_text "^application/pdf$"
+notmuch reindex '*'
+notmuch search id:871qo9p4tf.fsf@tethera.net > EXPECTED
+notmuch search id:871qo9p4tf.fsf@tethera.net and '"not really PDF"' > OUTPUT
+test_expect_equal_file_nonempty EXPECTED OUTPUT
+
+test_begin_subtest "as_text is bad regex"
+notmuch config set index.as_text '['
+notmuch reindex '*' >& OUTPUT
+cat<<EOF > EXPECTED
+Error in index.as_text: Invalid regular expression: [
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_done
diff --git a/test/T800-asan.sh b/test/T800-asan.sh
index 8607732e..9ce6baa7 100755
--- a/test/T800-asan.sh
+++ b/test/T800-asan.sh
@@ -2,14 +2,19 @@
 test_description='run code with ASAN enabled against the library'
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_ASAN -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_ASAN-0}" != "1" ]; then
     printf "Skipping due to missing ASAN support\n"
     test_done
 fi
 
+if [ -n "${LD_PRELOAD-}" ]; then
+    printf "Skipping due to ASAN LD_PRELOAD restrictions\n"
+    test_done
+fi
+
 add_email_corpus
 
-TEST_CFLAGS="-fsanitize=address"
+TEST_CFLAGS="${TEST_CFLAGS:-} -fsanitize=address"
 
 test_begin_subtest "open and destroy"
 test_C ${MAIL_DIR} ${NOTMUCH_CONFIG} <<EOF
diff --git a/test/T810-tsan.sh b/test/T810-tsan.sh
new file mode 100755
index 00000000..4071e296
--- /dev/null
+++ b/test/T810-tsan.sh
@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+
+test_directory=$(cd "$(dirname "${BASH_SOURCE[0]}")" > /dev/null && pwd)
+
+test_description='run code with TSan enabled against the library'
+# Note it is hard to ensure race conditions are deterministic so this
+# only provides best effort detection.
+
+. "$test_directory"/test-lib.sh || exit 1
+
+if [ "${NOTMUCH_HAVE_TSAN-0}" != "1" ]; then
+    printf "Skipping due to missing TSan support\n"
+    test_done
+fi
+
+export TSAN_OPTIONS="suppressions=$test_directory/T810-tsan.suppressions"
+TEST_CFLAGS="${TEST_CFLAGS:-} -fsanitize=thread"
+
+cp -r ${MAIL_DIR} ${MAIL_DIR}-2
+
+test_begin_subtest "create"
+test_C ${MAIL_DIR} ${MAIL_DIR}-2 <<EOF
+#include <notmuch-test.h>
+#include <pthread.h>
+
+void *thread (void *arg) {
+  char *mail_dir = arg;
+  /*
+   * Calls into notmuch_query_search_messages which was using the thread-unsafe
+   * Xapian::Query::MatchAll.
+   */
+  EXPECT0(notmuch_database_create (mail_dir, NULL));
+  return NULL;
+}
+
+int main (int argc, char **argv) {
+  pthread_t t1, t2;
+  EXPECT0(pthread_create (&t1, NULL, thread, argv[1]));
+  EXPECT0(pthread_create (&t2, NULL, thread, argv[2]));
+  EXPECT0(pthread_join (t1, NULL));
+  EXPECT0(pthread_join (t2, NULL));
+  return 0;
+}
+EOF
+cat <<EOF > EXPECTED
+== stdout ==
+== stderr ==
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+add_email_corpus
+rm -r ${MAIL_DIR}-2
+cp -r ${MAIL_DIR} ${MAIL_DIR}-2
+
+test_begin_subtest "query"
+test_C ${MAIL_DIR} ${MAIL_DIR}-2 <<EOF
+#include <notmuch-test.h>
+#include <pthread.h>
+
+void *thread (void *arg) {
+  char *mail_dir = arg;
+  notmuch_database_t *db;
+  /*
+   * 'from' is NOTMUCH_FIELD_PROBABILISTIC | NOTMUCH_FIELD_PROCESSOR and an
+   * empty string gets us to RegexpFieldProcessor::operator which was using
+   * the tread-unsafe Xapian::Query::MatchAll.
+   */
+  EXPECT0(notmuch_database_open_with_config (mail_dir,
+                                             NOTMUCH_DATABASE_MODE_READ_ONLY,
+                                             NULL, NULL, &db, NULL));
+  notmuch_query_t *query = notmuch_query_create (db, "from:\"\"");
+  notmuch_messages_t *messages;
+  EXPECT0(notmuch_query_search_messages (query, &messages));
+  return NULL;
+}
+
+int main (int argc, char **argv) {
+  pthread_t t1, t2;
+  EXPECT0(pthread_create (&t1, NULL, thread, argv[1]));
+  EXPECT0(pthread_create (&t2, NULL, thread, argv[2]));
+  EXPECT0(pthread_join (t1, NULL));
+  EXPECT0(pthread_join (t2, NULL));
+  return 0;
+}
+EOF
+cat <<EOF > EXPECTED
+== stdout ==
+== stderr ==
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_done
diff --git a/test/T810-tsan.suppressions b/test/T810-tsan.suppressions
new file mode 100644
index 00000000..80dc062f
--- /dev/null
+++ b/test/T810-tsan.suppressions
@@ -0,0 +1,3 @@
+# It's unclear how TSan-friendly GLib is:
+# https://gitlab.gnome.org/GNOME/glib/-/issues/1672
+called_from_lib:libglib*.so
diff --git a/test/T850-git.sh b/test/T850-git.sh
index 55cec78a..831e4678 100755
--- a/test/T850-git.sh
+++ b/test/T850-git.sh
@@ -2,7 +2,7 @@
 test_description='"notmuch git" to save and restore tags'
 . $(dirname "$0")/test-lib.sh || exit 1
 
-if [ $NOTMUCH_HAVE_SFSEXP -ne 1 ]; then
+if [ "${NOTMUCH_HAVE_SFSEXP-0}" != "1" ]; then
     printf "Skipping due to missing sfsexp library\n"
     test_done
 fi
@@ -233,6 +233,7 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "invoke as nmbug sets defaults"
+test_subtest_broken_for_installed
 "$NOTMUCH_BUILDDIR"/nmbug -ldebug status |& grep '^\(prefix\|repository\)' | notmuch_dir_sanitize > OUTPUT
 cat <<EOF > EXPECTED
 prefix = notmuch::
@@ -241,6 +242,7 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "env variable NOTMUCH_GIT_DIR works when invoked as nmbug"
+test_subtest_broken_for_installed
 NOTMUCH_GIT_DIR=`pwd`/foo "$NOTMUCH_BUILDDIR"/nmbug -ldebug status |& grep '^repository' | notmuch_dir_sanitize > OUTPUT
 cat <<EOF > EXPECTED
 repository = CWD/foo
@@ -256,6 +258,7 @@ test_expect_equal_file EXPECTED OUTPUT
 
 
 test_begin_subtest "env variable NOTMUCH_GIT_DIR overrides config when invoked as 'nmbug'"
+test_subtest_broken_for_installed
 notmuch config set git.path `pwd`/bar
 NOTMUCH_GIT_DIR=`pwd`/remote.git  "$NOTMUCH_BUILDDIR"/nmbug -ldebug status |& grep '^repository' | notmuch_dir_sanitize > OUTPUT
 notmuch config set git.path
@@ -274,6 +277,7 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "env variable NOTMUCH_GIT_PREFIX works when invoked as 'nmbug'"
+test_subtest_broken_for_installed
 NOTMUCH_GIT_PREFIX=env:: "$NOTMUCH_BUILDDIR"/nmbug -ldebug status |& grep '^prefix' | notmuch_dir_sanitize > OUTPUT
 cat <<EOF > EXPECTED
 prefix = env::
@@ -281,6 +285,7 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "env variable NOTMUCH_GIT_PREFIX works when invoked as nmbug"
+test_subtest_broken_for_installed
 NOTMUCH_GIT_PREFIX=foo:: "$NOTMUCH_BUILDDIR"/nmbug -ldebug status |& grep '^prefix' | notmuch_dir_sanitize > OUTPUT
 cat <<EOF > EXPECTED
 prefix = foo::
@@ -288,6 +293,7 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "env variable NOTMUCH_GIT_PREFIX overrides config when invoked as 'nmbug'"
+test_subtest_broken_for_installed
 notmuch config set git.tag_prefix config::
 NOTMUCH_GIT_PREFIX=env:: "$NOTMUCH_BUILDDIR"/nmbug -ldebug status |& grep '^prefix' | notmuch_dir_sanitize > OUTPUT
 notmuch config set git.path
diff --git a/test/corpora/indexing/fake-pdf:2,S b/test/corpora/indexing/fake-pdf:2,S
new file mode 100644
index 00000000..60a7a47f
--- /dev/null
+++ b/test/corpora/indexing/fake-pdf:2,S
@@ -0,0 +1,11 @@
+From: David Bremner <david@tethera.net>
+To: example@example.com
+Subject: attachment content type
+Date: Thu, 05 Jan 2023 08:02:36 -0400
+Message-ID: <871qo9p4tf.fsf@tethera.net>
+MIME-Version: 1.0
+Content-Type: application/pdf
+Content-Disposition: attachment; filename=fake.pdf
+Content-Transfer-Encoding: base64
+
+dGhpcyBpcyBub3QgcmVhbGx5IFBERgo=
\ No newline at end of file
diff --git a/test/emacs-tree.expected-output/inbox-outline b/test/emacs-tree.expected-output/inbox-outline
new file mode 100644
index 00000000..9119a916
--- /dev/null
+++ b/test/emacs-tree.expected-output/inbox-outline
@@ -0,0 +1,25 @@
+  2010-12-29  François Boulogne     ─►[aur-general] Guidelines: cp, mkdir vs install      (inbox unread)
+  2010-12-16  Olivier Berger        ─►Essai accentué                                      (inbox unread)
+  2009-11-18  Chris Wilson          ─►[notmuch] [PATCH 1/2] Makefile: evaluate pkg-config once (inbox unread)
+  2009-11-18  Alex Botero-Lowry     ┬►[notmuch] [PATCH] Error out if no query is supplied to search	instead of going into an infinite loop (attachment inbox unread)
+  2009-11-17  Ingmar Vanhassel      ┬►[notmuch] [PATCH] Typsos                            (inbox unread)
+  2009-11-17  Adrian Perez de Cast  ┬►[notmuch] Introducing myself                        (inbox signed unread)
+  2009-11-17  Israel Herraiz        ┬►[notmuch] New to the list                           (inbox unread)
+  2009-11-17  Jan Janak             ┬►[notmuch] What a great idea!                        (inbox unread)
+  2009-11-17  Jan Janak             ┬►[notmuch] [PATCH] Older versions of install do not support -C. (inbox unread)
+  2009-11-17  Aron Griffis          ┬►[notmuch] archive                                   (inbox unread)
+  2009-11-17  Keith Packard         ┬►[notmuch] [PATCH] Make notmuch-show 'X' (and 'x') commands remove	inbox (and unread) tags (inbox unread)
+  2009-11-17  Lars Kellogg-Stedman  ┬►[notmuch] Working with Maildir storage?             (inbox signed unread)
+  2009-11-17  Mikhail Gusarov       ┬►[notmuch] [PATCH 1/2] Close message file after parsing message	headers (inbox unread)
+  2009-11-18  Keith Packard         ┬►[notmuch] [PATCH] Create a default notmuch-show-hook that	highlights URLs and uses word-wrap (inbox unread)
+  2009-11-18  Alexander Botero-Low  ─►[notmuch] request for pull                          (inbox unread)
+  2009-11-18  Jjgod Jiang           ┬►[notmuch] Mac OS X/Darwin compatibility issues      (inbox unread)
+  2009-11-18  Rolland Santimano     ─►[notmuch] Link to mailing list archives ?           (inbox unread)
+  2009-11-18  Jan Janak             ─►[notmuch] [PATCH] notmuch new: Support for conversion of spool	subdirectories into tags (inbox unread)
+  2009-11-18  Stewart Smith         ─►[notmuch] [PATCH] count_files: sort directory in inode order before	statting (inbox unread)
+  2009-11-18  Stewart Smith         ─►[notmuch] [PATCH 2/2] Read mail directory in inode number order (inbox unread)
+  2009-11-18  Stewart Smith         ─►[notmuch] [PATCH] Fix linking with gcc to use g++ to link in C++	libs. (inbox unread)
+  2009-11-18  Lars Kellogg-Stedman  ┬►[notmuch] "notmuch help" outputs to stderr?         (attachment inbox signed unread)
+  2009-11-17  Mikhail Gusarov       ─►[notmuch] [PATCH] Handle rename of message file     (inbox unread)
+  2009-11-17  Alex Botero-Lowry     ┬►[notmuch] preliminary FreeBSD support               (attachment inbox unread)
+End of search results.
diff --git a/test/export-dirs.sh b/test/export-dirs.sh
index 0a048e1f..9bc99a2c 100644
--- a/test/export-dirs.sh
+++ b/test/export-dirs.sh
@@ -24,7 +24,7 @@ find_builddir () {
 if [[ -z "${NOTMUCH_BUILDDIR}" ]]; then
 	export NOTMUCH_BUILDDIR="$(find_builddir "$(pwd)")"
 
-	if [[ -z "${NOTMUCH_BUILDDIR}" ]]; then
+	if [ -z "${NOTMUCH_BUILDDIR}" -a "${NOTMUCH_TEST_INSTALLED-0}" = "0" ]; then
 		echo "Run tests in a subdir of built notmuch tree." >&2
 		exit 1
 	fi
diff --git a/test/notmuch-test b/test/notmuch-test
index 14747bdb..5d27e4d1 100755
--- a/test/notmuch-test
+++ b/test/notmuch-test
@@ -20,6 +20,14 @@ fi
 
 set -eu
 
+# Where to run the tests
+# XXX FIXME this code is duplicated with test-lib.sh
+if [[ -n "${NOTMUCH_BUILDDIR}" ]]; then
+    TEST_DIRECTORY=$NOTMUCH_BUILDDIR/test
+else
+    TEST_DIRECTORY=$NOTMUCH_SRCDIR/test
+fi
+
 TESTS=
 for test in ${NOTMUCH_TESTS-}; do
     TESTS="$TESTS $NOTMUCH_SRCDIR/test/$test"
@@ -80,7 +88,7 @@ for file in $TESTS
 do
     file=${file##*/} # drop leading path components
     file=${file%.sh} # drop trailing '.sh'
-    RESULT_FILES="$RESULT_FILES $NOTMUCH_BUILDDIR/test/test-results/$file"
+    RESULT_FILES="$RESULT_FILES $TEST_DIRECTORY/test-results/$file"
 done
 
 echo
@@ -94,6 +102,6 @@ if [ -n "$META_FAILURE" ]; then
 fi
 
 # Clean up
-rm -rf $NOTMUCH_BUILDDIR/test/test-results
+rm -rf $TEST_DIRECTORY/test-results
 
 exit $ev
diff --git a/test/setup.expected-output/config-with-comments b/test/setup.expected-output/config-with-comments
index d8397714..d925acea 100644
--- a/test/setup.expected-output/config-with-comments
+++ b/test/setup.expected-output/config-with-comments
@@ -1,7 +1,6 @@
 # .notmuch-config - Configuration file for the notmuch mail system
 #
 # For more information about notmuch, see https://notmuchmail.org
-
 # Database configuration
 #
 # The only value supported here is 'path' which should be the top-level
@@ -12,7 +11,6 @@
 #
 [database]
 path=/path/to/maildir
-
 # User configuration
 #
 # Here is where you can let notmuch know how you would like to be
@@ -32,7 +30,6 @@ path=/path/to/maildir
 name=Test Suite
 primary_email=test.suite@example.com
 other_email=another.suite@example.com
-
 # Configuration for "notmuch new"
 #
 # The following options are supported here:
@@ -49,7 +46,6 @@ other_email=another.suite@example.com
 #
 [new]
 tags=foo;bar;
-
 # Search configuration
 #
 # The following option is supported here:
@@ -61,7 +57,6 @@ tags=foo;bar;
 #
 [search]
 exclude_tags=baz
-
 # Maildir compatibility configuration
 #
 # The following option is supported here:
diff --git a/test/test-lib-common.sh b/test/test-lib-common.sh
index 18fa29c0..f5d72e12 100644
--- a/test/test-lib-common.sh
+++ b/test/test-lib-common.sh
@@ -24,7 +24,7 @@
 #
 type die >/dev/null 2>&1 || die () { echo "$@" >&2; exit 1; }
 
-if [[ -z "$NOTMUCH_SRCDIR" ]] || [[ -z "$NOTMUCH_BUILDDIR" ]]; then
+if [[ -z "$NOTMUCH_SRCDIR" ]] || [ -z "${NOTMUCH_TEST_INSTALLED-}" -a -z "$NOTMUCH_BUILDDIR" ]; then
 	echo "internal: srcdir or builddir not set" >&2
 	exit 1
 fi
@@ -61,7 +61,9 @@ LD_LIBRARY_PATH=${TEST_DIRECTORY%/*}/lib${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}
 export LD_LIBRARY_PATH
 
 # configure output
-. "$NOTMUCH_BUILDDIR/sh.config" || exit 1
+if [ -z "${NOTMUCH_TEST_INSTALLED-}" ]; then
+   . "$NOTMUCH_BUILDDIR/sh.config" || exit 1
+fi
 
 # load OS specifics
 if [[ -e "$NOTMUCH_SRCDIR/test/test-lib-$PLATFORM.sh" ]]; then
@@ -315,7 +317,12 @@ export PATH MANPATH
 
 # Test repository
 test="tmp.$(basename "$0" .sh)"
-TMP_DIRECTORY="$TEST_DIRECTORY/$test"
+if [ -z "${NOTMUCH_TEST_INSTALLED-}" ]; then
+    TMP_DIRECTORY="$TEST_DIRECTORY/$test"
+else
+    TMP_DIRECTORY=$(mktemp -d "${TMPDIR:-/tmp}/notmuch-$test.XXXXXX")
+fi
+
 test ! -z "$debug" || remove_tmp=$TMP_DIRECTORY
 rm -rf "$TMP_DIRECTORY" || {
 	GIT_EXIT_OK=t
@@ -323,6 +330,10 @@ rm -rf "$TMP_DIRECTORY" || {
 	exit 1
 }
 
+# Provide a guess at a usable Python, to support running tests without
+# running configure first.
+NOTMUCH_PYTHON=${NOTMUCH_PYTHON-python3}
+
 # A temporary home directory is needed by at least:
 # - emacs/"Sending a message via (fake) SMTP"
 # - emacs/"Reply within emacs"
diff --git a/test/test-lib-emacs.sh b/test/test-lib-emacs.sh
index ad4c4aeb..0ab58fc2 100644
--- a/test/test-lib-emacs.sh
+++ b/test/test-lib-emacs.sh
@@ -30,6 +30,7 @@ test_require_emacs () {
 # to the message and encrypting/signing.
 emacs_deliver_message () {
     local subject body smtp_dummy_pid smtp_dummy_port
+    test_subtest_broken_for_installed
     subject="$1"
     body="$2"
     shift 2
@@ -144,6 +145,13 @@ emacs_generate_script () {
 	# Construct a little test script here for the benefit of the user,
 	# (who can easily run "run_emacs" to get the same emacs environment
 	# for investigating any failures).
+    if [ -z "${NOTMUCH_TEST_INSTALLED-}" ]; then
+	find_notmuch_el='--directory "$NOTMUCH_BUILDDIR/emacs"'
+    else
+	### XXX FIXME: this should really use the installed emacs lisp files
+	find_notmuch_el='--directory "$NOTMUCH_SRCDIR/emacs"'
+    fi
+
 	cat <<EOF >"$TMP_DIRECTORY/run_emacs"
 #!/bin/sh
 export PATH=$PATH
@@ -158,8 +166,8 @@ export NOTMUCH_CONFIG=$NOTMUCH_CONFIG
 #
 # --load		Force loading of notmuch.el and test-lib.el
 
-exec ${TEST_EMACS} --quick \
-	--directory "$NOTMUCH_BUILDDIR/emacs" --load notmuch.el \
+exec ${TEST_EMACS} ${find_notmuch_el} --quick \
+	${EXTRA_DIR} --load notmuch.el \
 	--directory "$NOTMUCH_SRCDIR/test" --load test-lib.el \
 	"\$@"
 EOF
diff --git a/test/test-lib.el b/test/test-lib.el
index 79a9d4d6..4cfb8ef1 100644
--- a/test/test-lib.el
+++ b/test/test-lib.el
@@ -22,6 +22,15 @@
 
 ;;; Code:
 
+;; minimize impact of native compilation on the test suite.
+;; These are the Emacs 29.1 version of the variables.
+;; Leave trampolines enabled per Emacs upstream recommendations.
+;; It is important to set these variables before loading any
+;; .elc files.
+(setq native-comp-jit-compilation nil)
+(setq native-comp-speed -1)
+(setq native-comp-async-jobs-number 1)
+
 (require 'cl-lib)
 
 ;; Ensure that the dynamic variables that are defined by this library
@@ -205,3 +214,8 @@ running, quit if it terminated."
 ;; environments
 
 (setq mm-text-html-renderer 'html2text)
+
+;; Set our own default for message-hidden-headers, to avoid tests
+;; breaking when the Emacs default changes.
+(setq message-hidden-headers
+      '("^References:" "^Face:" "^X-Face:" "^X-Draft-From:"))
diff --git a/test/test-lib.sh b/test/test-lib.sh
index eec5c5b4..059e110c 100644
--- a/test/test-lib.sh
+++ b/test/test-lib.sh
@@ -29,8 +29,8 @@ shopt -u xpg_echo
 # Ensure NOTMUCH_SRCDIR and NOTMUCH_BUILDDIR are set.
 . $(dirname "$0")/export-dirs.sh || exit 1
 
-# It appears that people try to run tests without building...
-if [[ ! -x "$NOTMUCH_BUILDDIR/notmuch" ]]; then
+# We need either a built tree, or a promise of an installed notmuch
+if [ -z "${NOTMUCH_TEST_INSTALLED-}" -a ! -x "$NOTMUCH_BUILDDIR/notmuch" ]; then
 	echo >&2 'You do not seem to have built notmuch yet.'
 	exit 1
 fi
@@ -388,6 +388,14 @@ test_expect_equal_message_body () {
     test "$#" = 2 ||
 	error "bug in the test script: not 2 parameters to test_expect_equal_file"
 
+    for file in "$1" "$2"; do
+	if [ ! -s "$file" ]; then
+	    test_failure_ "Missing or zero length file: $file"
+	    inside_subtest=
+	    return 1
+	fi
+    done
+
     expected=$(sed '1,/^$/d' "$1")
     output=$(sed '1,/^$/d' "$2")
     test_expect_equal "$expected" "$output"
@@ -740,6 +748,18 @@ test_subtest_known_broken () {
 	test_subtest_known_broken_=t
 }
 
+test_subtest_broken_for_installed () {
+    if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+	test_subtest_known_broken_=t
+    fi
+}
+
+test_subtest_broken_for_root () {
+   if [ "$EUID" = "0" ]; then
+	test_subtest_known_broken_=t
+    fi
+}
+
 test_expect_success () {
 	exec 1>&6 2>&7		# Restore stdout and stderr
 	if [ -z "$inside_subtest" ]; then
@@ -915,11 +935,16 @@ make_shim () {
 }
 
 notmuch_with_shim () {
-    local base_name shim_file
-    base_name="$1"
+    local base_name shim_file notmuch_cmd
+    if [ -n "${NOTMUCH_TEST_INSTALLED-}" ]; then
+	notmuch_cmd="notmuch"
+    else
+	notmuch_cmd="notmuch-shared"
+    fi
+    base_name=$1
     shift
     shim_file="${base_name}.so"
-    LD_PRELOAD=${LD_PRELOAD:+:$LD_PRELOAD}:./${shim_file} notmuch-shared "$@"
+    LD_PRELOAD=${LD_PRELOAD:+:$LD_PRELOAD}:./${shim_file} $notmuch_cmd "$@"
 }
 
 # Creates a script that counts how much time it is executed and calls
@@ -971,7 +996,11 @@ test_init_ () {
 
 
 # Where to run the tests
-TEST_DIRECTORY=$NOTMUCH_BUILDDIR/test
+if [[ -n "${NOTMUCH_BUILDDIR}" ]]; then
+    TEST_DIRECTORY=$NOTMUCH_BUILDDIR/test
+else
+    TEST_DIRECTORY=$NOTMUCH_SRCDIR/test
+fi
 
 . "$NOTMUCH_SRCDIR/test/test-lib-common.sh" || exit 1
 
diff --git a/util/xapian-extra.h b/util/xapian-extra.h
new file mode 100644
index 00000000..39c7f48f
--- /dev/null
+++ b/util/xapian-extra.h
@@ -0,0 +1,15 @@
+#ifndef _XAPIAN_EXTRA_H
+#define _XAPIAN_EXTRA_H
+
+#include <string>
+#include <xapian.h>
+
+inline Xapian::Query
+xapian_query_match_all (void)
+{
+    // Xapian::Query::MatchAll isn't thread safe (a static object with reference
+    // counting) so instead reconstruct the equivalent on demand.
+    return Xapian::Query (std::string ());
+}
+
+#endif
diff --git a/version.txt b/version.txt
index c128d4d9..1cbc8125 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-0.37
+0.38
diff --git a/vim/README b/vim/README
index c137bacd..777c20c0 100644
--- a/vim/README
+++ b/vim/README
@@ -53,10 +53,10 @@ Enjoy ;)
 As an example to configure a key mapping to add the tag 'to-do' and archive,
 this is what I use:
 
-let g:notmuch_rb_custom_search_maps = {
+let g:notmuch_custom_search_maps = {
 	\ 't':		'search_tag("+to-do -inbox")',
 	\ }
 
-let g:notmuch_rb_custom_show_maps = {
+let g:notmuch_custom_show_maps = {
 	\ 't':		'show_tag("+to-do -inbox")',
 	\ }
diff --git a/vim/notmuch.txt b/vim/notmuch.txt
index 43741022..c98f2b53 100644
--- a/vim/notmuch.txt
+++ b/vim/notmuch.txt
@@ -89,7 +89,7 @@ s	Send
 CONFIGURATION					*notmuch-config*
 
 You can add the following configurations to your `.vimrc`, or
-`~/.vim/plugin/notmuch.vim`.
+`~/.vim/after/plugin/notmuch.vim`.
 
 						*g:notmuch_folders*
 
@@ -138,13 +138,13 @@ You can do the same for the thread view:
 
 If you want to count the threads instead of the messages in the folder view:
 >
-	let g:notmuch_folders_count_threads = 0
+	let g:notmuch_folders_count_threads = 1
 <
 
 						*g:notmuch_reader*
 						*g:notmuch_sendmail*
 
-You can also configure your externail mail reader and sendemail program:
+You can also configure your external mail reader and sendmail program:
 >
 	let g:notmuch_reader = 'mutt -f %s'
 	let g:notmuch_sendmail = 'sendmail'