IMAP: Fix SPECIAL-USE mailbox calculation.

The original algorithm to compute the SPECIAL-USE mailboxes was incorrect when multiple SPECIAL-USE mailboxes are present (e.g. multiple mailboxes in different namespaces), resulting in operations like "Delete", "Junk", etc. moving messages to the wrong folder. The logic has been amended to be more careful to ensure the right mailboxes are calculated.

Author: InterLinked1

evergreen.c

@@ -2140,7 +2140,7 @@ static int process_option(struct config *config, const char *optname, const char
 char *tmp;
 
 if (phony_options) {
-client_debug(5, "Processed option '%s'", optname);
+client_debug(10, "Processed option '%s'", optname);
 return 0;
 }
 
@@ -2353,7 +2353,7 @@ static int load_config(struct config *restrict config, int argc, char *argv[])
 process_option(config, long_options[option_index].name, optarg);
 break;
 default:
-client_debug(5, "Processed option '%c'", c);
+client_debug(10, "Processed option '%c'", c);
 break;
 }
 }

imap.c

@@ -951,6 +951,9 @@ static int ends_with(const char *s, const char *sub)
 static struct mailbox *find_specialuse_mailbox(struct client *client, int flag, const char *suffix)
 {
 int i;
+char parent[512], parent2[512];
+int has_parent_a, has_parent_b;
+size_t parentlen;
 struct mailbox *best = NULL;
 int max_common = 0, common;
 int found_specialuse = 0;
@@ -960,6 +963,9 @@ static struct mailbox *find_specialuse_mailbox(struct client *client, int flag,
  * but if there are multiple namespaces available to use, we may have
  * several Trash mailboxes, and we need to select the right one. */
 
+has_parent_a = mkparent(client, parent, sizeof(parent), client->sel_mbox->name);
+parentlen = strlen(parent);
+
 for (i = 0; i < client->num_mailboxes; i++) {
 if (!(client->mailboxes[i].flags & flag)) {
 continue;
@@ -972,8 +978,22 @@ static struct mailbox *find_specialuse_mailbox(struct client *client, int flag,
  * Other Users.jsmith.Sub.Folder
  * Other Users.jsmith.Trash is likely the correct trash mailbox,
  * not Trash, or anything else. */
+has_parent_b = mkparent(client, parent2, sizeof(parent2), client->mailboxes[i].name);
+if (has_parent_a != has_parent_b) {
+client_debug(5, "One has a parent and one doesn't: %s / %s, %d / %d\n", parent, parent2, has_parent_a, has_parent_b);
+continue;
+} else if (has_parent_a) {
+/* One parent must at least start with the other,
+ * for example, Gmail's special use folders are in
+ * subfolders of [Gmail]. */
+if (strncmp(parent, parent2, parentlen) && strncmp(parent, parent2, strlen(parent2))) {
+client_debug(5, "Different parents: %s != %s\n", parent, parent2);
+continue;
+}
+}
 common = num_common_prefix_chars(client->sel_mbox->name, client->mailboxes[i].name);
 if (common >= max_common) { /* >=, so even if 0 common prefix chars, Trash should override */
+client_debug(5, "%s is a better match than %s: %d", client->mailboxes[i].name, best ? best->name : "(empty)", common);
 best = &client->mailboxes[i];
 max_common = common;
 }

messages.c

@@ -152,7 +152,7 @@ void delete_message(struct client *client, struct message *msg)
 free_message(client, msg);
 }
 
-/* XXX For messages like move, when called from viewer (as opposed to message list),
+/* XXX For operations like move,
  * the number of messages is changed after we return, which clears the status pane,
  * so the status update is essentially lost. */
 int handle_message_op(struct client *client, struct pollfd *pfds, struct message *msg, struct message_data *mdata, int c)