[meld] filediff: Remove transient infobar messages on reload (ggo#158)

[Kai Willadsen <kaiw src gnome org>]

commit c859ae49e5626e58a40baf2157658348c2ef96f9
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Mon Jan 29 08:32:57 2018 +1000

    filediff: Remove transient infobar messages on reload (ggo#158)

 meld/filediff.py | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/meld/filediff.py b/meld/filediff.py
index 1fa94f41..c349a376 100644
--- a/meld/filediff.py
+++ b/meld/filediff.py
@@ -127,6 +127,9 @@ class FileDiff(MeldDoc, Component):
 
     # Identifiers for MsgArea messages
     (MSG_SAME, MSG_SLOW_HIGHLIGHT, MSG_SYNCPOINTS) = list(range(3))
+    # Transient messages that should be removed if any file in the
+    # comparison gets reloaded.
+    TRANSIENT_MESSAGES = {MSG_SAME, MSG_SLOW_HIGHLIGHT}
 
     __gsignals__ = {
         'next-conflict-changed': (
@@ -1053,6 +1056,10 @@ class FileDiff(MeldDoc, Component):
             tag = buf.get_tag_table().lookup("inline")
             buf.remove_tag(tag, buf.get_start_iter(), buf.get_end_iter())
 
+        for mgr in self.msgarea_mgr:
+            if mgr.get_msg_id() in self.TRANSIENT_MESSAGES:
+                mgr.clear()
+
     def set_files(self, gfiles, encodings=None):
         """Load the given files