mercurial/similar.py

match: add a subclass for dirstate normalizing of the matched patterns

This class is only needed on case insensitive filesystems, and only
for wdir context matches. It allows the user to not match the case of
the items in the filesystem- especially for naming directories, which
dirstate doesn't handle[1]. Making dirstate handle mismatched
directory cases is too expensive[2].

Since dirstate doesn't apply to committed csets, this is only created by
overriding basectx.match() in workingctx, and only on icasefs.  The default
arguments have been dropped, because the ctx must be passed to the matcher in
order to function.

For operations that can apply to both wdir and some other context, this ends up
normalizing the filename to the case as it exists in the filesystem, and using
that case for the lookup in the other context.  See the diff example in the
test.

Previously, given a directory with an inexact case:

  - add worked as expected

  - diff, forget and status would silently ignore the request

  - files would exit with 1

  - commit, revert and remove would fail (even when the commands leading up to
    them worked):

        $ hg ci -m "AbCDef" capsdir1/capsdir
        abort: CapsDir1/CapsDir: no match under directory!

        $ hg revert -r '.^' capsdir1/capsdir
        capsdir1\capsdir: no such file in rev 64dae27060b7

        $ hg remove capsdir1/capsdir
        not removing capsdir1\capsdir: no tracked files
        [1]

Globs are normalized, so that the -I and -X don't need to be specified with a
case match.  Without that, the second last remove (with -X) removes the files,
leaving nothing for the last remove.  However, specifying the files as
'glob:**.Txt' does not work.  Perhaps this requires 're.IGNORECASE'?

There are only a handful of places that create matchers directly, instead of
being routed through the context.match() method.  Some may benefit from changing
over to using ctx.match() as a factory function:

  revset.checkstatus()
  revset.contains()
  revset.filelog()
  revset._matchfiles()
  localrepository._loadfilter()
  ignore.ignore()
  fileset.subrepo()
  filemerge._picktool()
  overrides.addlargefiles()
  lfcommands.lfconvert()
  kwtemplate.__init__()
  eolfile.__init__()
  eolfile.checkrev()
  acl.buildmatch()

Currently, a toplevel subrepo can be named with an inexact case.  However, the
path auditor gets in the way of naming _anything_ in the subrepo if the top
level case doesn't match.  That is trickier to handle, because there's the user
provided case, the case in the filesystem, and the case stored in .hgsub.  This
can be fixed next cycle.

  --- a/tests/test-subrepo-deep-nested-change.t
  +++ b/tests/test-subrepo-deep-nested-change.t
  @@ -170,8 +170,15 @@
     R sub1/sub2/test.txt
     $ hg update -Cq
     $ touch sub1/sub2/folder/bar
  +#if icasefs
  +  $ hg addremove Sub1/sub2
  +  abort: path 'Sub1\sub2' is inside nested repo 'Sub1'
  +  [255]
  +  $ hg -q addremove sub1/sub2
  +#else
     $ hg addremove sub1/sub2
     adding sub1/sub2/folder/bar (glob)
  +#endif
     $ hg status -S
     A sub1/sub2/folder/bar
     ? foo/bar/abc

The narrowmatcher class may need to be tweaked when that is fixed.


[1] http://www.selenic.com/pipermail/mercurial-devel/2015-April/068183.html
[2] http://www.selenic.com/pipermail/mercurial-devel/2015-April/068191.html

# similar.py - mechanisms for finding similar files
#
# Copyright 2005-2007 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from i18n import _
import util
import mdiff
import bdiff

def _findexactmatches(repo, added, removed):
    '''find renamed files that have no changes

    Takes a list of new filectxs and a list of removed filectxs, and yields
    (before, after) tuples of exact matches.
    '''
    numfiles = len(added) + len(removed)

    # Get hashes of removed files.
    hashes = {}
    for i, fctx in enumerate(removed):
        repo.ui.progress(_('searching for exact renames'), i, total=numfiles)
        h = util.sha1(fctx.data()).digest()
        hashes[h] = fctx

    # For each added file, see if it corresponds to a removed file.
    for i, fctx in enumerate(added):
        repo.ui.progress(_('searching for exact renames'), i + len(removed),
                total=numfiles)
        h = util.sha1(fctx.data()).digest()
        if h in hashes:
            yield (hashes[h], fctx)

    # Done
    repo.ui.progress(_('searching for exact renames'), None)

def _findsimilarmatches(repo, added, removed, threshold):
    '''find potentially renamed files based on similar file content

    Takes a list of new filectxs and a list of removed filectxs, and yields
    (before, after, score) tuples of partial matches.
    '''
    copies = {}
    for i, r in enumerate(removed):
        repo.ui.progress(_('searching for similar files'), i,
                         total=len(removed))

        # lazily load text
        @util.cachefunc
        def data():
            orig = r.data()
            return orig, mdiff.splitnewlines(orig)

        def score(text):
            orig, lines = data()
            # bdiff.blocks() returns blocks of matching lines
            # count the number of bytes in each
            equal = 0
            matches = bdiff.blocks(text, orig)
            for x1, x2, y1, y2 in matches:
                for line in lines[y1:y2]:
                    equal += len(line)

            lengths = len(text) + len(orig)
            return equal * 2.0 / lengths

        for a in added:
            bestscore = copies.get(a, (None, threshold))[1]
            myscore = score(a.data())
            if myscore >= bestscore:
                copies[a] = (r, myscore)
    repo.ui.progress(_('searching'), None)

    for dest, v in copies.iteritems():
        source, score = v
        yield source, dest, score

def findrenames(repo, added, removed, threshold):
    '''find renamed files -- yields (before, after, score) tuples'''
    parentctx = repo['.']
    workingctx = repo[None]

    # Zero length files will be frequently unrelated to each other, and
    # tracking the deletion/addition of such a file will probably cause more
    # harm than good. We strip them out here to avoid matching them later on.
    addedfiles = set([workingctx[fp] for fp in added
            if workingctx[fp].size() > 0])
    removedfiles = set([parentctx[fp] for fp in removed
            if fp in parentctx and parentctx[fp].size() > 0])

    # Find exact matches.
    for (a, b) in _findexactmatches(repo,
            sorted(addedfiles), sorted(removedfiles)):
        addedfiles.remove(b)
        yield (a.path(), b.path(), 1.0)

    # If the user requested similar files to be matched, search for them also.
    if threshold < 1.0:
        for (a, b, score) in _findsimilarmatches(repo,
                sorted(addedfiles), sorted(removedfiles), threshold):
            yield (a.path(), b.path(), score)