Mercurial > hg
view tests/bruterebase.py @ 36672:9e7b14caf67f
xdiff: remove patience and histogram diff algorithms
Patience diff is the normal diff algorithm, plus some greediness that
unconditionally matches common common unique lines. That means it is easy to
construct cases to let it generate suboptimal result, like:
```
open('a', 'w').write('\n'.join(list('a' + 'x' * 300 + 'u' + 'x' * 700 + 'a\n')))
open('b', 'w').write('\n'.join(list('b' + 'x' * 700 + 'u' + 'x' * 300 + 'b\n')))
```
Patience diff has been advertised as being able to generate better results for
some C code changes. However, the more scientific way to do that is the
indention heuristic [1].
Since patience diff could generate suboptimal result more easily and its
"better" diff feature could be replaced by the new indention heuristic, let's
just remove it and its variant histogram diff to simplify the code.
[1]: https://github.com/git/git/commit/433860f3d0beb0c6f205290bd16cda413148f098
Test Plan:
`gcc -fPIC *.c --shared -o xdiff.so` still builds.
Differential Revision: https://phab.mercurial-scm.org/D2573
author | Jun Wu <quark@fb.com> |
---|---|
date | Sat, 03 Mar 2018 10:39:55 -0800 |
parents | 3b98ffd2dde3 |
children | 337d6e0fd9c9 |
line wrap: on
line source
# bruterebase.py - brute force rebase testing # # Copyright 2017 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. from __future__ import absolute_import from mercurial import ( error, registrar, revsetlang, ) from hgext import rebase try: xrange except NameError: xrange = range cmdtable = {} command = registrar.command(cmdtable) @command(b'debugbruterebase') def debugbruterebase(ui, repo, source, dest): """for every non-empty subset of source, run rebase -r subset -d dest Print one line summary for each subset. Assume obsstore is enabled. """ srevs = list(repo.revs(source)) with repo.wlock(), repo.lock(): repolen = len(repo) cl = repo.changelog def getdesc(rev): result = cl.changelogrevision(rev).description if rev >= repolen: result += b"'" return result for i in xrange(1, 2 ** len(srevs)): subset = [rev for j, rev in enumerate(srevs) if i & (1 << j) != 0] spec = revsetlang.formatspec(b'%ld', subset) tr = repo.transaction(b'rebase') tr.report = lambda x: 0 # hide "transaction abort" ui.pushbuffer() try: rebase.rebase(ui, repo, dest=dest, rev=[spec]) except error.Abort as ex: summary = b'ABORT: %s' % ex except Exception as ex: summary = b'CRASH: %s' % ex else: # short summary about new nodes cl = repo.changelog descs = [] for rev in xrange(repolen, len(repo)): desc = b'%s:' % getdesc(rev) for prev in cl.parentrevs(rev): if prev > -1: desc += getdesc(prev) descs.append(desc) descs.sort() summary = b' '.join(descs) ui.popbuffer() repo.vfs.tryunlink(b'rebasestate') subsetdesc = b''.join(getdesc(rev) for rev in subset) ui.write((b'%s: %s\n') % (subsetdesc.rjust(len(srevs)), summary)) tr.abort()