[PATCH evolve-ext] inhbit: don't crash on commit with no changes

[Laurent Charignon]

# HG changeset patch
# User Laurent Charignon <lcharignon at fb.com>
# Date 1432144712 25200
#      Wed May 20 10:58:32 2015 -0700
# Node ID f2dacc9545308e1805861ae39820efeea79b6e11
# Parent  bc9f871734475292c48dfe54e3040601b32ae4c8
inhbit: don't crash on commit with no changes

Before this patch inhibit would crash when running hg amend with no changes.
This patch fixes this case and adds a test to prevent regression.

diff --git a/hgext/inhibit.py b/hgext/inhibit.py
--- a/hgext/inhibit.py
+++ b/hgext/inhibit.py
@@ -43,7 +43,8 @@
 
         def commit(self, *args, **kwargs):
             newnode = super(obsinhibitedrepo, self).commit(*args, **kwargs)
-            _inhibitmarkers(repo, [newnode])
+            if newnode is not None:
+                _inhibitmarkers(repo, [newnode])
             return newnode
 
     repo.__class__ = obsinhibitedrepo
diff --git a/tests/test-inhibit.t b/tests/test-inhibit.t
--- a/tests/test-inhibit.t
+++ b/tests/test-inhibit.t
@@ -594,15 +594,22 @@
   |
   o  0:54ccbc537fc2 add cA
   
+  $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > EOF
+  $ echo "inhibit=$(echo $(dirname $TESTDIR))/hgext/inhibit.py" >> $HGRCPATH
+
+Empty commit
+  $ hg amend
+  nothing changed
+  [1]
 
 Inhibit should not work without directaccess
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > directaccess=!
   > EOF
-  $ echo "inhibit=$(echo $(dirname $TESTDIR))/hgext/inhibit.py" >> $HGRCPATH
-
   $ hg up 15
   abort: Cannot use inhibit without the direct access extension
   [255]
- 
+