[PATCH 1 of 4 V2] edit: allow to configure the suffix of the temporary filename

[Jordi Gutiérrez Hermoso]

# HG changeset patch
# User Jordi Gutiérrez Hermoso <jordigh at octave.org>
# Date 1458496541 14400
#      Sun Mar 20 13:55:41 2016 -0400
# Node ID c5bd96cb2fabf014db931430d266627633117dfd
# Parent  dfd5a6830ea7cd56909b6667c78ae122cc3a5aa1
edit: allow to configure the suffix of the temporary filename

Sometimes, we can pick a more appropriate default suffix than ".txt",
for example, diffs could have a ".diff" suffix.

diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -900,12 +900,15 @@ class ui(object):
             self.write(*msg, **opts)
 
     def edit(self, text, user, extra=None, editform=None, pending=None):
-        extra_defaults = { 'prefix': 'editor' }
+        extra_defaults = {
+            'prefix': 'editor',
+            'suffix': '.txt',
+        }
         if extra is not None:
             extra_defaults.update(extra)
         extra = extra_defaults
         (fd, name) = tempfile.mkstemp(prefix='hg-' + extra['prefix'] + '-',
-                                      suffix=".txt", text=True)
+                                      suffix=extra['suffix'], text=True)
         try:
             f = os.fdopen(fd, "w")
             f.write(text)