--- a/mercurial/commands.py	Sat May 12 00:24:07 2012 +0200
+++ b/mercurial/commands.py	Fri May 11 18:51:35 2012 +0200
@@ -2581,6 +2581,7 @@
     'graft',
     [('c', 'continue', False, _('resume interrupted graft')),
      ('e', 'edit', False, _('invoke editor on commit messages')),
+     ('', 'log', None, _('append graft info to log message')),
      ('D', 'currentdate', False,
       _('record the current date as commit date')),
      ('U', 'currentuser', False,
@@ -2599,6 +2600,11 @@
     Changesets that are ancestors of the current revision, that have
     already been grafted, or that are merges will be skipped.
 
+    If --log is specified, log messages will have a comment appended
+    of the form::
+
+      (grafted from CHANGESETHASH)
+
     If a graft merge results in conflicts, the graft process is
     interrupted so that the current merge can be manually resolved.
     Once all conflicts are addressed, the graft process can be
@@ -2748,7 +2754,10 @@
             date = ctx.date()
             if opts.get('date'):
                 date = opts['date']
-            node = repo.commit(text=ctx.description(), user=user,
+            message = ctx.description()
+            if opts.get('log'):
+                message += '\n(grafted from %s)' % ctx.hex()
+            node = repo.commit(text=message, user=user,
                         date=date, extra=extra, editor=editor)
             if node is None:
                 ui.status(_('graft for revision %s is empty\n') % ctx.rev())

--- a/tests/test-debugcomplete.t	Sat May 12 00:24:07 2012 +0200
+++ b/tests/test-debugcomplete.t	Fri May 11 18:51:35 2012 +0200
@@ -247,7 +247,7 @@
   debugsub: rev
   debugwalk: include, exclude
   debugwireargs: three, four, five, ssh, remotecmd, insecure
-  graft: continue, edit, currentdate, currentuser, date, user, tool, dry-run
+  graft: continue, edit, log, currentdate, currentuser, date, user, tool, dry-run
   grep: print0, all, text, follow, ignore-case, files-with-matches, line-number, rev, user, date, include, exclude
   heads: rev, topo, active, closed, style, template
   help: extension, command

--- a/tests/test-graft.t	Sat May 12 00:24:07 2012 +0200
+++ b/tests/test-graft.t	Fri May 11 18:51:35 2012 +0200
@@ -277,3 +277,13 @@
   $ hg graft tip
   skipping already grafted revision 13 (same origin 2)
   [255]
+
+Graft with --log
+
+  $ hg up -Cq 1
+  $ hg graft 3 --log -u foo
+  grafting revision 3
+  warning: can't find ancestor for 'c' copied from 'b'!
+  $ hg log --template '{rev} {parents} {desc}\n' -r tip
+  14 1:5d205f8b35b6  3
+  (grafted from 4c60f11aa304a54ae1c199feb94e7fc771e51ed8)