Mercurial > hg
view hgext/automv.py @ 34413:014d467f9d08
effectflag: store an empty effect flag for the moment
The idea behind effect flag is to store additional information in obs-markers
about what changed between a changeset and its successor(s). It's a low-level
information that comes without guarantees.
This information can be computed a posteriori, but only if we have all
changesets locally. This is not the case with distributed workflows where you
work with several people or on several computers (eg: laptop + build server).
Storing the effect-flag as a bitfield has several advantages:
- It's compact, we are using one byte per obs-marker at most for the effect-
flag.
- It's compoundable, the obsfate log approach needs to display evolve history
that could spans several obs-markers. Computing the effect-flag between a
changeset and its grand-grand-grand-successor is simple thanks to the
bitfield.
The effect-flag design has also some limitations:
- Evolving a changeset and reverting these changes just after would lead to
two obs-markers with the same effect-flag without information that the first
and third changesets are the same.
The effect-flag current design is a trade-off between compactness and
usefulness.
Storing this information helps commands to display a more complete and
understandable evolve history. For example, obslog (an Evolve command) use it
to improve its output:
x 62206adfd571 (34302) obscache: skip updating outdated obscache...
| rewritten(parent) by Matthieu Laneuville <matthieu.laneuville@octobus...
| rewritten(content) by Boris Feld <boris.feld@octobus.net>
The effect flag is stored in obs-markers metadata while we iterate on the
information we want to store. We plan to extend the existing obsmarkers
bit-field when the effect flag design will be stabilized.
It's different from the CommitCustody concept, effect-flag are not signed and
can be forged. It's also different from the operation metadata as the command
name (for example: amend) could alter a changeset in different ways (changing
the content with hg amend, changing the description with hg amend -e, changing
the user with hg amend -U). Also it's compatible with every custom command
that writes obs-markers without needing to be updated.
The effect-flag is placed behind an experimental flag set to off by default.
Hook the saving of effect flag in create markers, but store only an empty one
for the moment, I will refine the values in effect flag in following patches.
For more information, see:
https://www.mercurial-scm.org/wiki/ChangesetEvolutionDevel#Record_types_of_operation
Differential Revision: https://phab.mercurial-scm.org/D533
author | Boris Feld <boris.feld@octobus.net> |
---|---|
date | Thu, 06 Jul 2017 14:50:17 +0200 |
parents | 54bc88c56ec8 |
children | 38637dd39cfd |
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# 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 __future__ import absolute_import from mercurial.i18n import _ from mercurial import ( commands, copies, error, extensions, registrar, scmutil, similar ) configtable = {} configitem = registrar.configitem(configtable) configitem('automv', 'similarity', default=95, ) 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): """Hook to check for moves at commit time""" renames = None disabled = opts.pop('no_automv', False) if not disabled: threshold = ui.configint('automv', 'similarity') if not 0 <= threshold <= 100: raise error.Abort(_('automv.similarity must be between 0 and 100')) if threshold > 0: match = scmutil.match(repo[None], pats, opts) added, removed = _interestingfiles(repo, match) renames = _findrenames(repo, match, added, removed, threshold / 100.0) with repo.wlock(): if renames is not None: scmutil._markchanges(repo, (), (), renames) return orig(ui, repo, *pats, **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[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 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( _('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