[evolution-data-server/gnome-40] IMAPx: Change how Junk and NotJunk flags are handled

[Milan Crha <mcrha src gnome org>]

commit a201498e34fb4438b8cdbbc5c472821fb87b810f
Author: Milan Crha <mcrha redhat com>
Date:   Mon Jun 14 16:03:23 2021 +0200

    IMAPx: Change how Junk and NotJunk flags are handled
    
    It can happen that the server fails to unset the Junk flag on the message,
    thus the message can end with both Junk and NotJunk flags being set. Treat
    this state as the message doesn't have set the Junk flag, thus it'll stay
    at its folder, instead of being eventually moved back to the Junk folder.
    
    Related to https://gitlab.gnome.org/GNOME/evolution/-/issues/584

 src/camel/providers/imapx/camel-imapx-server.c | 15 ++++++++++++---
 src/camel/providers/imapx/camel-imapx-utils.c  | 14 ++++++++++++++
 2 files changed, 26 insertions(+), 3 deletions(-)
---
diff --git a/src/camel/providers/imapx/camel-imapx-server.c b/src/camel/providers/imapx/camel-imapx-server.c
index 36e638df9..b8905d072 100644
--- a/src/camel/providers/imapx/camel-imapx-server.c
+++ b/src/camel/providers/imapx/camel-imapx-server.c
@@ -4903,8 +4903,14 @@ camel_imapx_server_copy_message_sync (CamelIMAPXServer *is,
 
                                                if (remove_deleted_flags)
                                                        camel_message_info_set_flags (destination_info, 
CAMEL_MESSAGE_DELETED, 0);
-                                               if (remove_junk_flags)
+                                               if (remove_junk_flags) {
                                                        camel_message_info_set_flags (destination_info, 
CAMEL_MESSAGE_JUNK, 0);
+
+                                                       /* Force unset of the flag at the destination */
+                                                       camel_imapx_message_info_set_server_flags 
(CAMEL_IMAPX_MESSAGE_INFO (destination_info),
+                                                               camel_imapx_message_info_get_server_flags 
(CAMEL_IMAPX_MESSAGE_INFO (destination_info)) | CAMEL_MESSAGE_JUNK);
+                                                       camel_message_info_set_folder_flagged 
(destination_info, TRUE);
+                                               }
                                                imapx_copy_move_message_cache (folder, destination_folder, 
delete_originals || use_move_command,
                                                        camel_message_info_get_uid (source_info),
                                                        camel_message_info_get_uid (destination_info),
@@ -5955,9 +5961,12 @@ camel_imapx_server_sync_changes_sync (CamelIMAPXServer *is,
                        gboolean move_to_real_trash;
                        gboolean move_to_inbox;
 
+                       /* Some servers can leave the Junk flag even it had been unset, thus check also the 
NotJunk flag
+                          to avoid move back to the Junk folder. */
                        move_to_real_junk =
                                use_real_junk_path &&
-                               (flags & CAMEL_MESSAGE_JUNK);
+                               (flags & CAMEL_MESSAGE_JUNK) &&
+                               (camel_message_info_get_flags (info) & CAMEL_MESSAGE_NOTJUNK) == 0;
 
                        move_to_real_trash =
                                use_real_trash_path && remove_deleted_flags &&
@@ -6364,7 +6373,7 @@ camel_imapx_server_sync_changes_sync (CamelIMAPXServer *is,
                            !(has_flags & CAMEL_MESSAGE_DELETED)) {
                                set_folder_flagged = FALSE;
                        } else {
-                               /* to stare back the \Deleted flag */
+                               /* to store back the \Deleted flag */
                                set_server_flags &= ~CAMEL_MESSAGE_DELETED;
                                set_folder_flagged = TRUE;
                        }
diff --git a/src/camel/providers/imapx/camel-imapx-utils.c b/src/camel/providers/imapx/camel-imapx-utils.c
index 9bd729b28..fca9dad5a 100644
--- a/src/camel/providers/imapx/camel-imapx-utils.c
+++ b/src/camel/providers/imapx/camel-imapx-utils.c
@@ -365,6 +365,12 @@ imapx_update_message_info_flags (CamelMessageInfo *info,
        if ((permanent_flags & CAMEL_MESSAGE_USER) != 0 && imapx_update_user_flags (info, server_user_flags))
                changed = TRUE;
 
+       /* When both Junk and NotJunk are set, pretend the Junk flag is not set (this can happen when
+          the server fails to unset the Junk flag on message copy/move). */
+       if ((server_flags & CAMEL_MESSAGE_JUNK) != 0 && (server_flags & CAMEL_MESSAGE_NOTJUNK) != 0) {
+               changed = camel_message_info_set_flags (info, CAMEL_MESSAGE_JUNK, 0) || changed;
+       }
+
        return changed;
 }
 
@@ -386,6 +392,14 @@ imapx_set_message_info_flags_for_new_message (CamelMessageInfo *info,
 
        camel_message_info_take_user_tags (info, camel_name_value_array_copy (user_tags));
 
+       /* When the server has set both flags it means the user marked the message as not being junk;
+          in that case pretend the server has the Junk flag off, otherwise the message won't be
+          shown in its destination folder. */
+       if ((server_flags & CAMEL_MESSAGE_JUNK) != 0 &&
+           (server_flags & CAMEL_MESSAGE_NOTJUNK) != 0) {
+               camel_message_info_set_flags (info, CAMEL_MESSAGE_JUNK, 0);
+       }
+
        camel_message_info_set_folder_flagged (info, FALSE);
 }