lib/open: restore default database path of $HOME/mail

Although this default worked for "notmuch config get", it didn't work
most other places. Restore the previous functionality, with the
wrinkle that XDG locations will shadow $HOME/mail if they exist.

This fixes a bug reported by Jack Kamm in id:87eeefdc8b.fsf@gmail.com

lib/open.cc

@@ -209,8 +209,25 @@ _choose_database_path (void *ctx,
 	}
     }
     if (! *database_path) {
+	notmuch_status_t status;
+
 	*database_path = _xdg_dir (ctx, "XDG_DATA_HOME", ".local/share", profile);
-	*split = true;
+	status = _db_dir_exists (*database_path, message);
+	if (status) {
+	    *database_path = NULL;
+	} else {
+	    *split = true;
+	}
+    }
+
+    if (! *database_path) {
+	notmuch_status_t status;
+
+	*database_path = talloc_asprintf (ctx, "%s/mail", getenv ("HOME"));
+	status = _db_dir_exists (*database_path, message);
+	if (status) {
+	    *database_path = NULL;
+	}
     }
 
     if (*database_path == NULL) {

test/T055-path-config.sh

@@ -16,6 +16,7 @@ restore_config () {
     unset DATABASE_PATH
     unset NOTMUCH_PROFILE
     unset XAPIAN_PATH
+    rm -f "$HOME/mail"
     cp notmuch-config-backup.${test_name} ${NOTMUCH_CONFIG}
 }
 
@@ -42,6 +43,18 @@ symlink_config () {
     unset DATABASE_PATH
 }
 
+
+home_mail_config () {
+    local dir
+    backup_config
+    dir="${HOME}/mail"
+    ln -s $MAIL_DIR $dir
+    notmuch config set database.path
+    notmuch config set database.mail_root
+    XAPIAN_PATH="$MAIL_DIR/.notmuch/xapian"
+    unset DATABASE_PATH
+}
+
 xdg_config () {
     local dir
     local profile=${1:-default}
@@ -66,7 +79,7 @@ xdg_config () {
     notmuch --config=${CONFIG_PATH} config set database.path
 }
 
-for config in traditional split XDG XDG+profile symlink; do
+for config in traditional split XDG XDG+profile symlink home_mail; do
     #start each set of tests with an known set of messages
     add_email_corpus
 
@@ -90,6 +103,9 @@ for config in traditional split XDG XDG+profile symlink; do
 	symlink)
 	    symlink_config
 	    ;;
+	home_mail)
+	    home_mail_config
+	    ;;
     esac
 
     test_begin_subtest "count ($config)"
@@ -236,7 +252,9 @@ EOF
    test_begin_subtest "Config list ($config)"
    notmuch config list | notmuch_dir_sanitize | sed -e "s/^database.backup_dir=.*$/database.backup_dir/"  \
 						    -e "s/^database.hook_dir=.*$/database.hook_dir/" \
-						    -e "s/^database.path=.*$/database.path/" > OUTPUT
+						    -e "s/^database.path=.*$/database.path/"  \
+						    -e "s,^database.mail_root=CWD/home/mail,database.mail_root=MAIL_DIR," \
+						    > OUTPUT
    cat <<EOF > EXPECTED
 built_with.compact=true
 built_with.field_processor=true

test/T560-lib-error.sh

@@ -22,7 +22,7 @@ EOF
 cat <<'EOF' >EXPECTED
 == stdout ==
 == stderr ==
-Error: Cannot open database at CWD/home/.local/share/notmuch/default: No such file or directory.
+Error: could not locate database.
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
@@ -93,7 +93,7 @@ EOF
 cat <<'EOF' >EXPECTED
 == stdout ==
 == stderr ==
-Error: Cannot open database at CWD/home/.local/share/notmuch/default: No such file or directory.
+Error: could not locate database.
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 

test/T590-libconfig.sh

@@ -546,8 +546,8 @@ cat <<'EOF' >EXPECTED
 == stdout ==
 == stderr ==
 error opening database
-Something went wrong trying to read or write a file
-Error: Cannot open database at CWD/home/.local/share/notmuch/default: No such file or directory.
+No database found
+Error: could not locate database.
 
 EOF
 test_expect_equal_file EXPECTED OUTPUT