[gnome-directory-thumbnailer] core: Fix a potential assertion failure on an error handling path

[Philip Withnall <pwithnall src gnome org>]

commit 25c689462a6a97fc1a2d5fb4f22f7c1275f8b2e1
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Tue Jun 9 12:34:59 2015 +0100

    core: Fix a potential assertion failure on an error handling path
    
    If the enumeration loop iterates one or more times and chooses an
    interesting_file, then encounters an error getting some file information
    (which can happen part-way through enumeration with
    GLocalFileEnumerator), it will throw an error. The error code previously
    ignored existing interesting_files, and hence tripped the post-condition
    assertion (child_error == NULL || interesting_file_info == NULL).
    
    Fix that by ignoring errors if an interesting_file has already been
    found.
    
    https://retrace.fedoraproject.org/faf/problems/bthash/?bth=7c8a254ad589f1636cfc57d2921f51afba080609

 src/main.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/src/main.c b/src/main.c
index 86fc97c..f0c2364 100644
--- a/src/main.c
+++ b/src/main.c
@@ -261,8 +261,19 @@ pick_interesting_file_for_directory (GFile *input_directory, GFileInfo **file_in
 
        g_file_enumerator_close (enumerator, NULL, NULL);  /* ignore errors from this */
 
-       /* Did we break out of the loop because of an error? */
+       /* Did we break out of the loop because of an error? If so, and we
+        * already have an interesting file, squash the error and continue with
+        * that file. */
        if (child_error != NULL) {
+               if (interesting_file != NULL) {
+                       gchar *path = g_file_get_path (input_directory);
+                       g_debug ("Ignoring error enumerating directory ‘%s’; "
+                                "found interesting file already.", path);
+                       g_free (path);
+
+                       g_clear_error (&child_error);
+               }
+
                goto done;
        }