# HG changeset patch
# User Pierre-Yves David <pierre-yves.david@fb.com>
# Date 1444362146 25200
# Node ID 13fc93fb7fbeecebe566c0a34746b13692073e6f
# Parent  558dd43b599d6858f0f298caa698742490069c2c
patch: add topic to exported patch

If used Mercurial supports it, we add a topic header to patches.

diff --git a/src/topic/__init__.py b/src/topic/__init__.py
--- a/src/topic/__init__.py
+++ b/src/topic/__init__.py
@@ -213,6 +213,12 @@
     rebase = extensions.find("rebase")
     extensions.wrapfunction(rebase, '_makeextrafn', newmakeextrafn)
 
+def _exporttopic(seq, ctx):
+    topic = ctx.topic()
+    if topic:
+        return 'EXP-Topic %s'  % topic
+    return None
+
 extensions.afterloaded('rebase', _fixrebase)
 
 entry = extensions.wrapcommand(commands.table, 'commit', commitwrap)
@@ -223,3 +229,7 @@
 extensions.wrapfunction(merge, 'update', mergeupdatewrap)
 topicrevset.modsetup()
 cmdutil.summaryhooks.add('topic', summaryhook)
+
+if util.safehasattr(cmdutil, 'extraexport'):
+    cmdutil.extraexport.append('topic')
+    cmdutil.extraexportmap['topic'] = _exporttopic
diff --git a/tests/test-topic.t b/tests/test-topic.t
--- a/tests/test-topic.t
+++ b/tests/test-topic.t
@@ -137,6 +137,26 @@
   adding manifests
   adding file changes
   added 5 changesets with 5 changes to 4 files
+
+Export
+
+  $ hg -R pinky export
+  # HG changeset patch
+  # User test
+  # Date 0 0
+  #      Thu Jan 01 00:00:00 1970 +0000
+  # Node ID 7c34953036d6a36eae468c550d0592b89ee8bffc
+  # Parent  fb147b0b417c25ca15547cd945acf51cf8dcaf02
+  # EXP-Topic narf
+  narf!
+  
+  diff -r fb147b0b417c -r 7c34953036d6 alpha
+  --- a/alpha	Thu Jan 01 00:00:00 1970 +0000
+  +++ b/alpha	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,2 +1,3 @@
+   file alpha
+   topic work
+  +narf!!!
 Now that we've pushed to brain, the work done on narf is no longer a
 draft, so we won't see that topic name anymore: