[meld] filediff: Handle initial loads for missing gfiles

[Kai Willadsen <kaiw src gnome org>]

commit bab6479de8e79f24171a26d2e055af3ff686c81e
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Dec 10 07:43:04 2017 +1000

    filediff: Handle initial loads for missing gfiles
    
    This can happen if e.g., the user selects one file in the new comparison
    UI but leaves the other blank. Without the buffer-is-loaded logic
    addition here, the UI just stalls in a loading state.

 meld/filediff.py |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/meld/filediff.py b/meld/filediff.py
index 50e6407..2615c1f 100644
--- a/meld/filediff.py
+++ b/meld/filediff.py
@@ -1057,11 +1057,12 @@ class FileDiff(melddoc.MeldDoc, gnomeglade.Component):
 
         encodings = encodings or ((None,) * len(gfiles))
 
-        files = [
-            (pane, gfile, encoding)
-            for pane, (gfile, encoding) in enumerate(zip(gfiles, encodings))
-            if gfile
-        ]
+        files = []
+        for pane, (gfile, encoding) in enumerate(zip(gfiles, encodings)):
+            if gfile:
+                files.append((pane, gfile, encoding))
+            else:
+                self.textbuffer[pane].data.loaded = True
 
         if not files:
             self.scheduler.add_task(self._compare_files_internal())