[meld/Python3] meldbuffer: Don't update recorded disk mtime for errors/missing files

[Kai Willadsen <kaiw src gnome org>]

commit 1424df9654f99a05ce16b8fcf9a9d7fa1c3eab7b
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Jul 10 09:44:14 2016 +1000

    meldbuffer: Don't update recorded disk mtime for errors/missing files
    
    Most commonly this is an issue where a file notification event happens
    for a deleted file that is then replaced by an external program. In
    this case we don't want to invalidate our recorded on-disk mtime
    because it's still the last valid time we saw for this file.

 meld/meldbuffer.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/meld/meldbuffer.py b/meld/meldbuffer.py
index 186d624..451a60e 100644
--- a/meld/meldbuffer.py
+++ b/meld/meldbuffer.py
@@ -164,7 +164,7 @@ class MeldBufferData(GObject.GObject):
         mtime = self._query_mtime(f)
         if self._disk_mtime and mtime and mtime > self._disk_mtime:
             self.emit('file-changed')
-        self._disk_mtime = mtime
+        self._disk_mtime = mtime or self._disk_mtime
 
     @property
     def gfile(self):