Merge branch 'release'

reference loop fixes to be included in 0.26.2

NEWS

@@ -1,3 +1,14 @@
+Notmuch 0.26.2 (UNRELEASED)
+===========================
+
+Library Changes
+---------------
+
+Make thread indexing more robust against reference loops
+
+  Choose a thread root by date in case of reference loops. Fix a
+  related abort in `notmuch show`.
+
 Notmuch 0.26.1 (2018-04-02)
 ===========================
 

lib/thread.cc

@@ -390,11 +390,15 @@ _thread_add_matched_message (notmuch_thread_t *thread,
 static void
 _resolve_thread_relationships (notmuch_thread_t *thread)
 {
-    notmuch_message_node_t *node;
+    notmuch_message_node_t *node, *first_node;
     notmuch_message_t *message, *parent;
     const char *in_reply_to;
 
-    for (node = thread->message_list->head; node; node = node->next) {
+    first_node = thread->message_list->head;
+    if (! first_node)
+	return;
+
+    for (node = first_node->next; node; node = node->next) {
 	message = node->message;
 	in_reply_to = _notmuch_message_get_in_reply_to (message);
 	if (in_reply_to && strlen (in_reply_to) &&
@@ -406,6 +410,25 @@ _resolve_thread_relationships (notmuch_thread_t *thread)
 	    _notmuch_message_list_add_message (thread->toplevel_list, message);
     }
 
+    /*
+     * if we reach the end of the list without finding a top-level
+     * message, that means the thread is a cycle (or set of cycles)
+     * and any message can be considered top-level.  Choose the oldest
+     * message, which happens to be first in our list.
+     */
+    if (first_node) {
+	message = first_node->message;
+	in_reply_to = _notmuch_message_get_in_reply_to (message);
+	if (thread->toplevel_list->head &&
+	    in_reply_to && strlen (in_reply_to) &&
+	    g_hash_table_lookup_extended (thread->message_hash,
+					  in_reply_to, NULL,
+					  (void **) &parent))
+	    _notmuch_message_add_reply (parent, message);
+	else
+	    _notmuch_message_list_add_message (thread->toplevel_list, message);
+    }
+
     /* XXX: After scanning through the entire list looking for parents
      * via "In-Reply-To", we should do a second pass that looks at the
      * list of messages IDs in the "References" header instead. (And

test/T050-new.sh

@@ -354,4 +354,17 @@ exit status: 75
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
+add_email_corpus broken
+test_begin_subtest "reference loop does not crash"
+test_expect_code 0 "notmuch show --format=json id:mid-loop-12@example.org id:mid-loop-21@example.org > OUTPUT"
+
+test_begin_subtest "reference loop ordered by date"
+threadid=$(notmuch search --output=threads  id:mid-loop-12@example.org)
+notmuch show --format=mbox $threadid | grep '^Date'  > OUTPUT
+cat <<EOF > EXPECTED
+Date: Thu, 16 Jun 2016 22:14:41 -0400
+Date: Fri, 17 Jun 2016 22:14:41 -0400
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
 test_done

test/corpora/broken/loop/loop-12

@@ -0,0 +1,8 @@
+From: Alice <alice@example.org>
+To: Daniel <daniel@example.org>
+Subject: referencing in-reply-to-loop-21
+Message-ID: <mid-loop-12@example.org>
+In-Reply-To: <mid-loop-21@example.org>
+Date: Thu, 16 Jun 2016 22:14:41 -0400
+
+Note Message-ID and In-Reply-To: in file in-reply-to-loop-21

test/corpora/broken/loop/loop-21

@@ -0,0 +1,8 @@
+From: Alice <alice@example.org>
+To: Daniel <daniel@example.org>
+Subject: referencing in-reply-to-loop-12
+Message-ID: <mid-loop-21@example.org>
+In-Reply-To: <mid-loop-12@example.org>
+Date: Fri, 17 Jun 2016 22:14:41 -0400
+
+Note Message-ID and In-Reply-To: in file in-reply-to-loop-12