--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/automv.py	Mon Feb 08 13:52:51 2016 +0000
@@ -0,0 +1,83 @@
+# automv.py
+#
+# Copyright 2013-2016 Facebook, Inc.
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+"""Check for unrecorded moves at commit time (EXPERIMENTAL)
+
+This extension checks at commit/amend time if any of the committed files
+comes from an unrecorded mv.
+
+The threshold at which a file is considered a move can be set with the
+``automv.similarity`` config option; the default value is 1.00.
+
+"""
+from __future__ import absolute_import
+
+from mercurial import (
+    commands,
+    copies,
+    extensions,
+    scmutil,
+    similar
+)
+from mercurial.i18n import _
+
+def extsetup(ui):
+    entry = extensions.wrapcommand(
+        commands.table, 'commit', mvcheck)
+    entry[1].append(
+        ('', 'no-automv', None,
+         _('disable automatic file move detection')))
+
+def mvcheck(orig, ui, repo, *pats, **opts):
+    disabled = opts.pop('no_automv', False)
+    if not disabled:
+        threshold = float(ui.config('automv', 'similarity', '1.00'))
+        if threshold > 0:
+            match = scmutil.match(repo[None], pats, opts)
+            added, removed = _interestingfiles(repo, match)
+            renames = _findrenames(repo, match, added, removed, threshold)
+            _markchanges(repo, renames)
+
+    # developer config: automv.testmode
+    if not ui.configbool('automv', 'testmode'):
+        return orig(ui, repo, *pats, **opts)
+
+def _interestingfiles(repo, matcher):
+    stat = repo.status(repo['.'], repo[None], matcher)
+    added = stat[1]
+    removed = stat[2]
+
+    copy = copies._forwardcopies(repo['.'], repo[None], matcher)
+    # remove the copy files for which we already have copy info
+    added = [f for f in added if f not in copy]
+
+    return added, removed
+
+def _findrenames(repo, matcher, added, removed, similarity):
+    """Find renames from removed files of the current commit/amend files
+    to the added ones"""
+    renames = {}
+    if similarity > 0:
+        for src, dst, score in similar.findrenames(
+                repo, added, removed, similarity):
+            if repo.ui.verbose:
+                repo.ui.status(
+                    _('detected move of %s as %s (%d%% similar)\n') % (
+                        matcher.rel(src), matcher.rel(dst), score * 100))
+            renames[dst] = src
+    if renames:
+        repo.ui.status(_('detected move of %d files\n') % len(renames))
+    return renames
+
+def _markchanges(repo, renames):
+    """Marks the files in renames as copied."""
+    wctx = repo[None]
+    wlock = repo.wlock()
+    try:
+        for dst, src in renames.iteritems():
+            wctx.copy(src, dst)
+    finally:
+        wlock.release()