tags_to_maildir_flags: Don't rename if no flags change

notmuch_message_tags_to_maildir_flags() unconditionally moves messages from
maildir directory "new/" to maildir directory "cur/", which makes messages lose
their "new" status in the MUA. However some users want to keep this "new"
status after, for instance, an auto-tagging of new messages.

However, as Austin mentioned and according to the maildir specification,
messages living in "new/" are not allowed to have flags, even if mutt allows it
to happen. For this reason, this patch prevents moving messages from "new/" to
"cur/", only if no flags have to be changed. It's hopefully enough to satisfy
mutt (and maybe other MUAs showing the "new" status) users checking the "new"
status.

Changelog:
* v2: Fix bool type as well as NULL returned despite having no errors (Austin
      Clements)
* v4: Tag the related test (contributed by Michal Sojka) as working

Signed-off-by: Louis Rilling <l.rilling@av7.net>

[Condition for keeping messages in new/ was extended to satisfy all
 tests from the previous patch. -Michal Sojka]

[Added by David Bremner, to keep the tests passing at each commit]

update insert tests for new maildir synchronization rules

As of id:1355952747-27350-4-git-send-email-sojkam1@fel.cvut.cz
we are more conservative about moving messages from ./new to ./cur.
This updates the insert tests to match

3 files changed, 15 insertions, 5 deletions

diff --git a/lib/message.cc b/lib/message.cc
index c4261e61..1b463795 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -1195,7 +1195,9 @@ _get_maildir_flag_actions (notmuch_message_t *message,
  * compute the new maildir filename.
  *
  * If the existing filename is in the directory "new", the new
- * filename will be in the directory "cur".
+ * filename will be in the directory "cur", except for the case when
+ * no flags are changed and the existing filename does not contain
+ * maildir info (starting with ",2:").
  *
  * After a sequence of ":2," in the filename, any subsequent
  * single-character flags will be added or removed according to the
@@ -1218,6 +1220,7 @@ _new_maildir_filename (void *ctx,
     char *filename_new, *dir;
     char flag_map[128];
     int flags_in_map = 0;
+    notmuch_bool_t flags_changed = FALSE;
     unsigned int i;
     char *s;
 
@@ -1258,6 +1261,7 @@ _new_maildir_filename (void *ctx,
 	if (flag_map[flag] == 0) {
 	    flag_map[flag] = 1;
 	    flags_in_map++;
+	    flags_changed = TRUE;
 	}
     }
 
@@ -1266,9 +1270,16 @@ _new_maildir_filename (void *ctx,
 	if (flag_map[flag]) {
 	    flag_map[flag] = 0;
 	    flags_in_map--;
+	    flags_changed = TRUE;
 	}
     }
 
+    /* Messages in new/ without maildir info can be kept in new/ if no
+     * flags have changed. */
+    dir = (char *) _filename_is_in_maildir (filename);
+    if (dir && STRNCMP_LITERAL (dir, "new/") == 0 && !*info && !flags_changed)
+	return talloc_strdup (ctx, filename);
+
     filename_new = (char *) talloc_size (ctx,
 					 info - filename +
 					 strlen (":2,") + flags_in_map + 1);
diff --git a/test/insert b/test/insert
index 021edb62..1718120d 100755
--- a/test/insert
+++ b/test/insert
@@ -82,7 +82,7 @@ gen_insert_msg
 notmuch insert --folder=Drafts < "$gen_msg_filename"
 output=$(notmuch search --output=files folder:Drafts)
 dirname=$(dirname "$output")
-test_expect_equal "$dirname" "$MAIL_DIR/Drafts/cur"
+test_expect_equal "$dirname" "$MAIL_DIR/Drafts/new"
 
 test_begin_subtest "Insert message into folder, add/remove tags"
 gen_insert_msg
@@ -99,14 +99,14 @@ gen_insert_msg
 notmuch insert --folder=F --create-folder +folder < "$gen_msg_filename"
 output=$(notmuch search --output=files folder:F tag:folder)
 basename=$(basename "$output")
-test_expect_equal_file "$gen_msg_filename" "$MAIL_DIR/F/cur/${basename}"
+test_expect_equal_file "$gen_msg_filename" "$MAIL_DIR/F/new/${basename}"
 
 test_begin_subtest "Insert message, create subfolder"
 gen_insert_msg
 notmuch insert --folder=F/G/H/I/J --create-folder +folder < "$gen_msg_filename"
 output=$(notmuch search --output=files folder:F/G/H/I/J tag:folder)
 basename=$(basename "$output")
-test_expect_equal_file "$gen_msg_filename" "${MAIL_DIR}/F/G/H/I/J/cur/${basename}"
+test_expect_equal_file "$gen_msg_filename" "${MAIL_DIR}/F/G/H/I/J/new/${basename}"
 
 test_begin_subtest "Insert message, create existing subfolder"
 gen_insert_msg
diff --git a/test/maildir-sync b/test/maildir-sync
index b2ac89ff..33d2c585 100755
--- a/test/maildir-sync
+++ b/test/maildir-sync
@@ -84,7 +84,6 @@ test_expect_equal "$output" "No new mail."
 # creating all necessary database state for those directories.
 
 test_begin_subtest "Adding non-maildir tags does not move message from new to cur"
-test_subtest_known_broken
 add_message [subject]='"Message to stay in new"' \
     [date]='"Sat, 01 Jan 2000 12:00:00 -0000"' \
     [filename]='message-to-stay-in-new' [dir]=new