hgext/convert/git.py

convert: detect removal of ".gitmodules" at git source revisions correctly

Before this patch, all operations applied on ".gitmodules" at git
source revisions are treated as modification, even if they are
actually removal of it.

If removal of ".gitmodules" is treated as modification unexpectedly,
"hg convert" is aborted by the exception raised in
"retrievegitmodules()" for ".gitmodules" at the git source revision
removing it, because that revision doesn't have any information of
".gitmodules".

This patch detects removal of ".gitmodules" at git source revisions
correctly.

If ".gitmodules" is removed at the git source revision, this patch
records "hex(nullid)" as the contents hash value for ".hgsub" and
".hgsubstate" at the destination revision.

This patch makes "getfile()" raise IOError also for ".hgstatus" and
".hgsubstate" if the contents hash value is "hex(nullid)", and this
tells removal of ".hgstatus" and ".hgsubstate" at the destination
revision to "localrepository.commitctx()" correctly.

For files other than ".hgstatus" and ".hgsubstate", checking the
contents hash value in "getfile()" may be redundant, because
"catfile()" for them also does so.

But this patch chooses writing it only once at the beginning of
"getfile()", to avoid writing same code twice both for ".hgsub" and
".hgsubstate" separately.

# git.py - git support for the convert extension
#
#  Copyright 2005-2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import os
import subprocess
from mercurial import util, config
from mercurial.node import hex, nullid
from mercurial.i18n import _

from common import NoRepo, commit, converter_source, checktool

class submodule(object):
    def __init__(self, path, node, url):
        self.path = path
        self.node = node
        self.url = url

    def hgsub(self):
        return "%s = [git]%s" % (self.path, self.url)

    def hgsubstate(self):
        return "%s %s" % (self.node, self.path)

class convert_git(converter_source):
    # Windows does not support GIT_DIR= construct while other systems
    # cannot remove environment variable. Just assume none have
    # both issues.
    if util.safehasattr(os, 'unsetenv'):
        def gitopen(self, s, err=None):
            prevgitdir = os.environ.get('GIT_DIR')
            os.environ['GIT_DIR'] = self.path
            try:
                if err == subprocess.PIPE:
                    (stdin, stdout, stderr) = util.popen3(s)
                    return stdout
                elif err == subprocess.STDOUT:
                    return self.popen_with_stderr(s)
                else:
                    return util.popen(s, 'rb')
            finally:
                if prevgitdir is None:
                    del os.environ['GIT_DIR']
                else:
                    os.environ['GIT_DIR'] = prevgitdir
    else:
        def gitopen(self, s, err=None):
            if err == subprocess.PIPE:
                (sin, so, se) = util.popen3('GIT_DIR=%s %s' % (self.path, s))
                return so
            elif err == subprocess.STDOUT:
                    return self.popen_with_stderr(s)
            else:
                return util.popen('GIT_DIR=%s %s' % (self.path, s), 'rb')

    def popen_with_stderr(self, s):
        p = subprocess.Popen(s, shell=True, bufsize=-1,
                             close_fds=util.closefds,
                             stdin=subprocess.PIPE,
                             stdout=subprocess.PIPE,
                             stderr=subprocess.STDOUT,
                             universal_newlines=False,
                             env=None)
        return p.stdout

    def gitread(self, s):
        fh = self.gitopen(s)
        data = fh.read()
        return data, fh.close()

    def __init__(self, ui, path, rev=None):
        super(convert_git, self).__init__(ui, path, rev=rev)

        if os.path.isdir(path + "/.git"):
            path += "/.git"
        if not os.path.exists(path + "/objects"):
            raise NoRepo(_("%s does not look like a Git repository") % path)

        checktool('git', 'git')

        self.path = path
        self.submodules = []

    def getheads(self):
        if not self.rev:
            heads, ret = self.gitread('git rev-parse --branches --remotes')
            heads = heads.splitlines()
        else:
            heads, ret = self.gitread("git rev-parse --verify %s" % self.rev)
            heads = [heads[:-1]]
        if ret:
            raise util.Abort(_('cannot retrieve git heads'))
        return heads

    def catfile(self, rev, type):
        if rev == hex(nullid):
            raise IOError
        data, ret = self.gitread("git cat-file %s %s" % (type, rev))
        if ret:
            raise util.Abort(_('cannot read %r object at %s') % (type, rev))
        return data

    def getfile(self, name, rev):
        if rev == hex(nullid):
            raise IOError
        if name == '.hgsub':
            data = '\n'.join([m.hgsub() for m in self.submoditer()])
            mode = ''
        elif name == '.hgsubstate':
            data = '\n'.join([m.hgsubstate() for m in self.submoditer()])
            mode = ''
        else:
            data = self.catfile(rev, "blob")
            mode = self.modecache[(name, rev)]
        return data, mode

    def submoditer(self):
        null = hex(nullid)
        for m in sorted(self.submodules, key=lambda p: p.path):
            if m.node != null:
                yield m

    def parsegitmodules(self, content):
        """Parse the formatted .gitmodules file, example file format:
        [submodule "sub"]\n
        \tpath = sub\n
        \turl = git://giturl\n
        """
        self.submodules = []
        c = config.config()
        # Each item in .gitmodules starts with \t that cant be parsed
        c.parse('.gitmodules', content.replace('\t',''))
        for sec in c.sections():
            s = c[sec]
            if 'url' in s and 'path' in s:
                self.submodules.append(submodule(s['path'], '', s['url']))

    def retrievegitmodules(self, version):
        modules, ret = self.gitread("git show %s:%s" % (version, '.gitmodules'))
        if ret:
            raise util.Abort(_('cannot read submodules config file in %s') %
                             version)
        self.parsegitmodules(modules)
        for m in self.submodules:
            node, ret = self.gitread("git rev-parse %s:%s" % (version, m.path))
            if ret:
                continue
            m.node = node.strip()

    def getchanges(self, version):
        self.modecache = {}
        fh = self.gitopen("git diff-tree -z --root -m -r %s" % version)
        changes = []
        seen = set()
        entry = None
        subexists = False
        subdeleted = False
        for l in fh.read().split('\x00'):
            if not entry:
                if not l.startswith(':'):
                    continue
                entry = l
                continue
            f = l
            if f not in seen:
                seen.add(f)
                entry = entry.split()
                h = entry[3]
                p = (entry[1] == "100755")
                s = (entry[1] == "120000")

                if f == '.gitmodules':
                    subexists = True
                    if entry[4] == 'D':
                        subdeleted = True
                        changes.append(('.hgsub', hex(nullid)))
                    else:
                        changes.append(('.hgsub', ''))
                elif entry[1] == '160000' or entry[0] == ':160000':
                    subexists = True
                else:
                    self.modecache[(f, h)] = (p and "x") or (s and "l") or ""
                    changes.append((f, h))
            entry = None
        if fh.close():
            raise util.Abort(_('cannot read changes in %s') % version)

        if subexists:
            if subdeleted:
                changes.append(('.hgsubstate', hex(nullid)))
            else:
                self.retrievegitmodules(version)
                changes.append(('.hgsubstate', ''))
        return (changes, {})

    def getcommit(self, version):
        c = self.catfile(version, "commit") # read the commit hash
        end = c.find("\n\n")
        message = c[end + 2:]
        message = self.recode(message)
        l = c[:end].splitlines()
        parents = []
        author = committer = None
        for e in l[1:]:
            n, v = e.split(" ", 1)
            if n == "author":
                p = v.split()
                tm, tz = p[-2:]
                author = " ".join(p[:-2])
                if author[0] == "<": author = author[1:-1]
                author = self.recode(author)
            if n == "committer":
                p = v.split()
                tm, tz = p[-2:]
                committer = " ".join(p[:-2])
                if committer[0] == "<": committer = committer[1:-1]
                committer = self.recode(committer)
            if n == "parent":
                parents.append(v)

        if committer and committer != author:
            message += "\ncommitter: %s\n" % committer
        tzs, tzh, tzm = tz[-5:-4] + "1", tz[-4:-2], tz[-2:]
        tz = -int(tzs) * (int(tzh) * 3600 + int(tzm))
        date = tm + " " + str(tz)

        c = commit(parents=parents, date=date, author=author, desc=message,
                   rev=version)
        return c

    def gettags(self):
        tags = {}
        alltags = {}
        fh = self.gitopen('git ls-remote --tags "%s"' % self.path,
                          err=subprocess.STDOUT)
        prefix = 'refs/tags/'

        # Build complete list of tags, both annotated and bare ones
        for line in fh:
            line = line.strip()
            if line.startswith("error:") or line.startswith("fatal:"):
                raise util.Abort(_('cannot read tags from %s') % self.path)
            node, tag = line.split(None, 1)
            if not tag.startswith(prefix):
                continue
            alltags[tag[len(prefix):]] = node
        if fh.close():
            raise util.Abort(_('cannot read tags from %s') % self.path)

        # Filter out tag objects for annotated tag refs
        for tag in alltags:
            if tag.endswith('^{}'):
                tags[tag[:-3]] = alltags[tag]
            else:
                if tag + '^{}' in alltags:
                    continue
                else:
                    tags[tag] = alltags[tag]

        return tags

    def getchangedfiles(self, version, i):
        changes = []
        if i is None:
            fh = self.gitopen("git diff-tree --root -m -r %s" % version)
            for l in fh:
                if "\t" not in l:
                    continue
                m, f = l[:-1].split("\t")
                changes.append(f)
        else:
            fh = self.gitopen('git diff-tree --name-only --root -r %s '
                              '"%s^%s" --' % (version, version, i + 1))
            changes = [f.rstrip('\n') for f in fh]
        if fh.close():
            raise util.Abort(_('cannot read changes in %s') % version)

        return changes

    def getbookmarks(self):
        bookmarks = {}

        # Interesting references in git are prefixed
        prefix = 'refs/heads/'
        prefixlen = len(prefix)

        # factor two commands
        gitcmd = { 'remote/': 'git ls-remote --heads origin',
                          '': 'git show-ref'}

        # Origin heads
        for reftype in gitcmd:
            try:
                fh = self.gitopen(gitcmd[reftype], err=subprocess.PIPE)
                for line in fh:
                    line = line.strip()
                    rev, name = line.split(None, 1)
                    if not name.startswith(prefix):
                        continue
                    name = '%s%s' % (reftype, name[prefixlen:])
                    bookmarks[name] = rev
            except Exception:
                pass

        return bookmarks

    def checkrevformat(self, revstr, mapname='splicemap'):
        """ git revision string is a 40 byte hex """
        self.checkhexformat(revstr, mapname)