automv: lock the repository before searching for renames

I detected this while debugging something else.

hgext/automv.py

@@ -1,124 +1,126
 # 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. This option takes a percentage between 0
 (disabled) and 100 (files must be identical), the default is 95.
 
 """
 
 # Using 95 as a default similarity is based on an analysis of the mercurial
 # repositories of the cpython, mozilla-central & mercurial repositories, as
 # well as 2 very large facebook repositories. At 95 50% of all potential
 # missed moves would be caught, as well as correspond with 87% of all
 # explicitly marked moves.  Together, 80% of moved files are 95% similar or
 # more.
 #
 # See http://markmail.org/thread/5pxnljesvufvom57 for context.
 
 
 from mercurial.i18n import _
 from mercurial import (
     commands,
     copies,
     error,
     extensions,
     pycompat,
     registrar,
     scmutil,
     similar,
 )
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 
 configitem(
     b'automv',
     b'similarity',
     default=95,
 )
 
 
 def extsetup(ui):
     entry = extensions.wrapcommand(commands.table, b'commit', mvcheck)
     entry[1].append(
         (b'', b'no-automv', None, _(b'disable automatic file move detection'))
     )
 
 
 def mvcheck(orig, ui, repo, *pats, **opts):
     """Hook to check for moves at commit time"""
     opts = pycompat.byteskwargs(opts)
     renames = None
     disabled = opts.pop(b'no_automv', False)
-    if not disabled:
-        threshold = ui.configint(b'automv', b'similarity')
-        if not 0 <= threshold <= 100:
-            raise error.Abort(_(b'automv.similarity must be between 0 and 100'))
-        if threshold > 0:
-            match = scmutil.match(repo[None], pats, opts)
-            added, removed = _interestingfiles(repo, match)
-            uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True)
-            renames = _findrenames(
-                repo, uipathfn, added, removed, threshold / 100.0
-            )
+    with repo.wlock():
+        if not disabled:
+            threshold = ui.configint(b'automv', b'similarity')
+            if not 0 <= threshold <= 100:
+                raise error.Abort(
+                    _(b'automv.similarity must be between 0 and 100')
+                )
+            if threshold > 0:
+                match = scmutil.match(repo[None], pats, opts)
+                added, removed = _interestingfiles(repo, match)
+                uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True)
+                renames = _findrenames(
+                    repo, uipathfn, added, removed, threshold / 100.0
+                )
 
-    with repo.wlock():
         if renames is not None:
             with repo.dirstate.changing_files(repo):
                 # XXX this should be wider and integrated with the commit
                 # transaction. At the same time as we do the `addremove` logic
                 # for commit.  However we can't really do better with the
                 # current extension structure, and this is not worse than what
                 # happened before.
                 scmutil._markchanges(repo, (), (), renames)
         return orig(ui, repo, *pats, **pycompat.strkwargs(opts))
 
 
 def _interestingfiles(repo, matcher):
     """Find what files were added or removed in this commit.
 
     Returns a tuple of two lists: (added, removed). Only files not *already*
     marked as moved are included in the added list.
 
     """
     stat = repo.status(match=matcher)
     added = stat.added
     removed = stat.removed
 
     copy = copies.pathcopies(repo[b'.'], 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, uipathfn, added, removed, similarity):
     """Find what files in added are really moved files.
 
     Any file named in removed that is at least similarity% similar to a file
     in added is seen as a rename.
 
     """
     renames = {}
     if similarity > 0:
         for src, dst, score in similar.findrenames(
             repo, added, removed, similarity
         ):
             if repo.ui.verbose:
                 repo.ui.status(
                     _(b'detected move of %s as %s (%d%% similar)\n')
                     % (uipathfn(src), uipathfn(dst), score * 100)
                 )
             renames[dst] = src
     if renames:
         repo.ui.status(_(b'detected move of %d files\n') % len(renames))
     return renames