Comment 228 for bug 1512120

I am sending a simple patch which wraps the renaming code and the folder monitor code in a mutex.

I suppose that the main reason for the crash is that when we call in thunar-file.c:1932:

g_file_set_display_name (file->gfile, name, cancellable, error);

this call sends a signal which is connected to the folder monitor. The folder monitor runs on another thread. The thunar_folder_monitor function gets called immediately and it sends some signals which call thunar_list_model_files_added, which then uses thunar_file_compare_by_name as comparison function.

The problem is, we have our original, "renaming" thread, which at one point calls thunar_file_info_clear. If we are at the end of this clearing function and then the thread switches and the code from thunar_file_compare_by_name continues, it will segfault because all members of ThunarFile structure are now null.

The solution is to prevent starting the code of thunar_folder_monitor until the renaming procedure is completed so all ThunarFile members are already updated.

So, I have added an extern "rename" mutex which is acquired in these two functions.

The mutex must be acquired before the call to g_file_set_display_name.

Also, there is a simple method to trigger the segfault:
- add a 1-second sleep as the last line of the thunar_file_info_clear function
- add a 0.5-second sleep as the first line of the thunar_folder_monitor
(you can add some conditional checks to prevent long pause when loading Thunar)
- compile and test