mercurial/ignore.py

localrepo.commit: normalize commit message even for rawcommit.

This normalization consists of:
- stripping trailing whitespace
- always using "\n" as the line separator

I think the main reason rawcommit was skipping this normalization was
an attempt to preserve hashes during an hg->hg conversion.

While this is a nice goal, it's not particularly interesting in
practice.  Since SHA-1 is so strong, the only safe way to do it is to
have absolutely identical revisions.  But:

- if the original revision was created with a recent version of hg,
  the commit message will be the same, with or without that
  normalization

- if it was created with an ancient version of hg that didn't do any
  normalization, even if the commit message is identical, the file list
  in the changelog is likely to be different (e.g. no removed files),
  and there were some old issues with e.g. extra file merging, which
  will end up changing the hash anyway

- in any case, if one *really* has to preserve hashes, it's easier
  (and faster) to fake a partial conversion using something like:

  hg clone -U -r rev orig-repo new-repo
  hg -R new-repo log --template '#node# #node#\n' > new-repo/.hg/shamap

Additionally, we've had some reports of problems arising from this lack
of normalization - e.g. issue871, and a user that was wondering why
hg export/hg import was not preserving hashes when there was nothing
unusual going on (it was just import doing the normalization that had
been skipped).

This also means that it's even more unlikely to get identical revisions
when going $VCS->hg->$VCS.

# ignore.py - ignored file handling for mercurial
#
# Copyright 2007 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

from i18n import _
import util, re

_commentre = None

def _parselines(fp):
    for line in fp:
        if "#" in line:
            global _commentre
            if not _commentre:
                _commentre = re.compile(r'((^|[^\\])(\\\\)*)#.*')
            # remove comments prefixed by an even number of escapes
            line = _commentre.sub(r'\1', line)
            # fixup properly escaped comments that survived the above
            line = line.replace("\\#", "#")
        line = line.rstrip()
        if line:
            yield line

def ignore(root, files, warn):
    '''return the contents of .hgignore files as a list of patterns.

    the files parsed for patterns include:
    .hgignore in the repository root
    any additional files specified in the [ui] section of ~/.hgrc

    trailing white space is dropped.
    the escape character is backslash.
    comments start with #.
    empty lines are skipped.

    lines can be of the following formats:

    syntax: regexp # defaults following lines to non-rooted regexps
    syntax: glob   # defaults following lines to non-rooted globs
    re:pattern     # non-rooted regular expression
    glob:pattern   # non-rooted glob
    pattern        # pattern of the current default type'''

    syntaxes = {'re': 'relre:', 'regexp': 'relre:', 'glob': 'relglob:'}
    pats = {}
    for f in files:
        try:
            pats[f] = []
            fp = open(f)
            syntax = 'relre:'
            for line in _parselines(fp):
                if line.startswith('syntax:'):
                    s = line[7:].strip()
                    try:
                        syntax = syntaxes[s]
                    except KeyError:
                        warn(_("%s: ignoring invalid syntax '%s'\n") % (f, s))
                    continue
                pat = syntax + line
                for s, rels in syntaxes.items():
                    if line.startswith(rels):
                        pat = line
                        break
                    elif line.startswith(s+':'):
                        pat = rels + line[len(s)+1:]
                        break
                pats[f].append(pat)
        except IOError, inst:
            if f != files[0]:
                warn(_("skipping unreadable ignore file '%s': %s\n") %
                     (f, inst.strerror))

    allpats = []
    [allpats.extend(patlist) for patlist in pats.values()]
    if not allpats:
        return util.never

    try:
        files, ignorefunc, anypats = (
            util.matcher(root, inc=allpats, src='.hgignore'))
    except util.Abort:
        # Re-raise an exception where the src is the right file
        for f, patlist in pats.items():
            files, ignorefunc, anypats = (
                util.matcher(root, inc=patlist, src=f))

    return ignorefunc