[balsa] mailbox-local: Check for error return value

[Peter Bloomfield <peterb src gnome org>]

commit 179dbfeab6ddb99676a06fd63ad273532ae5ec2f
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Fri Jan 10 17:46:12 2020 -0500

    mailbox-local: Check for error return value
    
    * libbalsa/mailbox_local.c (libbalsa_mailbox_local_set_threading):
      check the value returned by libbalsa_mailbox_prepare_threading();
      if it is FALSE, the operation failed, perhaps because the mailbox was
      closed or finalized, so just quit.

 ChangeLog                | 10 ++++++++++
 libbalsa/mailbox_local.c | 14 ++++++++++----
 2 files changed, 20 insertions(+), 4 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index ff69f0ae2..43b77b77a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2020-01-10  Peter Bloomfield  <pbloomfield bellsouth net>
+
+       mailbox-local: Check for error return value
+
+       * libbalsa/mailbox_local.c
+       (libbalsa_mailbox_local_set_threading): check the value returned
+       by libbalsa_mailbox_prepare_threading(); if it is FALSE, the
+       operation failed, perhaps because the mailbox was closed or
+       finalized, so just quit.
+
 2020-01-10  Peter Bloomfield  <pbloomfield bellsouth net>
 
        Guard against mailbox being closed or finalized during a call to
diff --git a/libbalsa/mailbox_local.c b/libbalsa/mailbox_local.c
index 8ef0e5e88..151691fe1 100644
--- a/libbalsa/mailbox_local.c
+++ b/libbalsa/mailbox_local.c
@@ -1183,6 +1183,7 @@ libbalsa_mailbox_local_set_threading(LibBalsaMailbox * mailbox,
         gboolean natural = (thread_type == LB_MAILBOX_THREADING_FLAT
                             && libbalsa_mailbox_get_sort_field(mailbox) ==
                             LB_MAILBOX_SORT_NO);
+        gboolean ok = TRUE;
 
         libbalsa_mailbox_set_msg_tree(mailbox, g_node_new(NULL));
         if (!lbm_local_restore_tree(local, &total)) {
@@ -1193,20 +1194,25 @@ libbalsa_mailbox_local_set_threading(LibBalsaMailbox * mailbox,
         libbalsa_mailbox_set_msg_tree_changed(mailbox, FALSE);
 
         if (total < libbalsa_mailbox_total_messages(mailbox)) {
-            if (!natural)
+            if (!natural) {
                 /* Get message info for all messages that weren't restored,
                  * so we can thread and sort them correctly before the
                  * mailbox is displayed. */
-                libbalsa_mailbox_prepare_threading(mailbox, total);
-            libbalsa_mailbox_local_load_messages(mailbox, total);
+                ok = libbalsa_mailbox_prepare_threading(mailbox, total);
+            }
+            if (ok)
+                libbalsa_mailbox_local_load_messages(mailbox, total);
+            else
+                return; /* Something bad happened */
         }
 
 #if defined(DEBUG_LOADING_AND_THREADING)
         printf("after load messages: time=%lu\n", (unsigned long) time(NULL));
 #endif
-        if (natural)
+        if (natural) {
             /* No need to thread. */
             return;
+        }
     }
 
     if (libbalsa_am_i_subthread()) {