view hgext/convert/git.py @ 30660:1f21a6835604

convert: add config option to copy extra keys from Git commits

Git commit objects support storing arbitrary key-value metadata. While
there is no user-facing mechanism in Git to record these values, some
tools do record data here.

Currently, `hg convert` only handles the "author," "committer," and
"parent" keys in Git commit objects. All other keys are ignored. This
means that any custom keys are lost when converting Git repos to
Mercurial.

This patch implements support for copying a whitelist of extra keys
from Git commit objects to the "extras" dict of the destination. As
the added tests demonstate, this allows extra metadata to be preserved
during the conversion process.

This patch stops short of converting all metadata to "extras." We could
potentially implement this via `convert.git.extrakeys=*` or similar.
But copying everything by default is a bit dangerous because if Git
adds new keys to commit objects, we could find ourselves copying
things that shouldn't be copied!

This patch also assumes the source key is the same as the destination
key. We could implement support for prefixing the output key to
distinguish it as coming from Git. But until this feature is needed,
I'm inclined to hold off implementing it.

# 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.
from __future__ import absolute_import

import os

from mercurial.i18n import _
from mercurial import (
    config,
    error,
    node as nodemod,
)

from . import (
    common,
)

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)

# Keys in extra fields that should not be copied if the user requests.
bannedextrakeys = set([
    # Git commit object built-ins.
    'tree',
    'parent',
    'author',
    'committer',
    # Mercurial built-ins.
    'branch',
    'close',
])

class convert_git(common.converter_source, common.commandline):
    # Windows does not support GIT_DIR= construct while other systems
    # cannot remove environment variable. Just assume none have
    # both issues.

    def _gitcmd(self, cmd, *args, **kwargs):
        return cmd('--git-dir=%s' % self.path, *args, **kwargs)

    def gitrun0(self, *args, **kwargs):
        return self._gitcmd(self.run0, *args, **kwargs)

    def gitrun(self, *args, **kwargs):
        return self._gitcmd(self.run, *args, **kwargs)

    def gitrunlines0(self, *args, **kwargs):
        return self._gitcmd(self.runlines0, *args, **kwargs)

    def gitrunlines(self, *args, **kwargs):
        return self._gitcmd(self.runlines, *args, **kwargs)

    def gitpipe(self, *args, **kwargs):
        return self._gitcmd(self._run3, *args, **kwargs)

    def __init__(self, ui, path, revs=None):
        super(convert_git, self).__init__(ui, path, revs=revs)
        common.commandline.__init__(self, ui, 'git')

        # Pass an absolute path to git to prevent from ever being interpreted
        # as a URL
        path = os.path.abspath(path)

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

        # The default value (50) is based on the default for 'git diff'.
        similarity = ui.configint('convert', 'git.similarity', default=50)
        if similarity < 0 or similarity > 100:
            raise error.Abort(_('similarity must be between 0 and 100'))
        if similarity > 0:
            self.simopt = ['-C%d%%' % similarity]
            findcopiesharder = ui.configbool('convert', 'git.findcopiesharder',
                                             False)
            if findcopiesharder:
                self.simopt.append('--find-copies-harder')

            renamelimit = ui.configint('convert', 'git.renamelimit',
                                       default=400)
            self.simopt.append('-l%d' % renamelimit)
        else:
            self.simopt = []

        common.checktool('git', 'git')

        self.path = path
        self.submodules = []

        self.catfilepipe = self.gitpipe('cat-file', '--batch')

        self.copyextrakeys = self.ui.configlist('convert', 'git.extrakeys')
        banned = set(self.copyextrakeys) & bannedextrakeys
        if banned:
            raise error.Abort(_('copying of extra key is forbidden: %s') %
                              _(', ').join(sorted(banned)))

    def after(self):
        for f in self.catfilepipe:
            f.close()

    def getheads(self):
        if not self.revs:
            output, status = self.gitrun('rev-parse', '--branches', '--remotes')
            heads = output.splitlines()
            if status:
                raise error.Abort(_('cannot retrieve git heads'))
        else:
            heads = []
            for rev in self.revs:
                rawhead, ret = self.gitrun('rev-parse', '--verify', rev)
                heads.append(rawhead[:-1])
                if ret:
                    raise error.Abort(_('cannot retrieve git head "%s"') % rev)
        return heads

    def catfile(self, rev, type):
        if rev == nodemod.nullhex:
            raise IOError
        self.catfilepipe[0].write(rev+'\n')
        self.catfilepipe[0].flush()
        info = self.catfilepipe[1].readline().split()
        if info[1] != type:
            raise error.Abort(_('cannot read %r object at %s') % (type, rev))
        size = int(info[2])
        data = self.catfilepipe[1].read(size)
        if len(data) < size:
            raise error.Abort(_('cannot read %r object at %s: unexpected size')
                             % (type, rev))
        # read the trailing newline
        self.catfilepipe[1].read(1)
        return data

    def getfile(self, name, rev):
        if rev == nodemod.nullhex:
            return None, None
        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 = nodemod.nullhex
        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 whitespace that cant be parsed
        c.parse('.gitmodules', '\n'.join(line.strip() for line in
                               content.split('\n')))
        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.gitrun('show', '%s:%s' % (version, '.gitmodules'))
        if ret:
            # This can happen if a file is in the repo that has permissions
            # 160000, but there is no .gitmodules file.
            self.ui.warn(_("warning: cannot read submodules config file in "
                           "%s\n") % version)
            return

        try:
            self.parsegitmodules(modules)
        except error.ParseError:
            self.ui.warn(_("warning: unable to parse .gitmodules in %s\n")
                         % version)
            return

        for m in self.submodules:
            node, ret = self.gitrun('rev-parse', '%s:%s' % (version, m.path))
            if ret:
                continue
            m.node = node.strip()

    def getchanges(self, version, full):
        if full:
            raise error.Abort(_("convert from git does not support --full"))
        self.modecache = {}
        cmd = ['diff-tree','-z', '--root', '-m', '-r'] + self.simopt + [version]
        output, status = self.gitrun(*cmd)
        if status:
            raise error.Abort(_('cannot read changes in %s') % version)
        changes = []
        copies = {}
        seen = set()
        entry = None
        subexists = [False]
        subdeleted = [False]
        difftree = output.split('\x00')
        lcount = len(difftree)
        i = 0

        skipsubmodules = self.ui.configbool('convert', 'git.skipsubmodules',
                                            False)
        def add(entry, f, isdest):
            seen.add(f)
            h = entry[3]
            p = (entry[1] == "100755")
            s = (entry[1] == "120000")
            renamesource = (not isdest and entry[4][0] == 'R')

            if f == '.gitmodules':
                if skipsubmodules:
                    return

                subexists[0] = True
                if entry[4] == 'D' or renamesource:
                    subdeleted[0] = True
                    changes.append(('.hgsub', nodemod.nullhex))
                else:
                    changes.append(('.hgsub', ''))
            elif entry[1] == '160000' or entry[0] == ':160000':
                if not skipsubmodules:
                    subexists[0] = True
            else:
                if renamesource:
                    h = nodemod.nullhex
                self.modecache[(f, h)] = (p and "x") or (s and "l") or ""
                changes.append((f, h))

        while i < lcount:
            l = difftree[i]
            i += 1
            if not entry:
                if not l.startswith(':'):
                    continue
                entry = l.split()
                continue
            f = l
            if entry[4][0] == 'C':
                copysrc = f
                copydest = difftree[i]
                i += 1
                f = copydest
                copies[copydest] = copysrc
            if f not in seen:
                add(entry, f, False)
            # A file can be copied multiple times, or modified and copied
            # simultaneously. So f can be repeated even if fdest isn't.
            if entry[4][0] == 'R':
                # rename: next line is the destination
                fdest = difftree[i]
                i += 1
                if fdest not in seen:
                    add(entry, fdest, True)
                    # .gitmodules isn't imported at all, so it being copied to
                    # and fro doesn't really make sense
                    if f != '.gitmodules' and fdest != '.gitmodules':
                        copies[fdest] = f
            entry = None

        if subexists[0]:
            if subdeleted[0]:
                changes.append(('.hgsubstate', nodemod.nullhex))
            else:
                self.retrievegitmodules(version)
                changes.append(('.hgsubstate', ''))
        return (changes, copies, set())

    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
        extra = {}
        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 n in self.copyextrakeys:
                extra[n] = 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 = common.commit(parents=parents, date=date, author=author,
                          desc=message,
                          rev=version,
                          extra=extra)
        return c

    def numcommits(self):
        output, ret = self.gitrunlines('rev-list', '--all')
        if ret:
            raise error.Abort(_('cannot retrieve number of commits in %s') \
                              % self.path)
        return len(output)

    def gettags(self):
        tags = {}
        alltags = {}
        output, status = self.gitrunlines('ls-remote', '--tags', self.path)

        if status:
            raise error.Abort(_('cannot read tags from %s') % self.path)
        prefix = 'refs/tags/'

        # Build complete list of tags, both annotated and bare ones
        for line in output:
            line = line.strip()
            if line.startswith("error:") or line.startswith("fatal:"):
                raise error.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

        # 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:
            output, status = self.gitrunlines('diff-tree', '--root', '-m',
                                              '-r', version)
            if status:
                raise error.Abort(_('cannot read changes in %s') % version)
            for l in output:
                if "\t" not in l:
                    continue
                m, f = l[:-1].split("\t")
                changes.append(f)
        else:
            output, status = self.gitrunlines('diff-tree', '--name-only',
                                              '--root', '-r', version,
                                              '%s^%s' % (version, i + 1), '--')
            if status:
                raise error.Abort(_('cannot read changes in %s') % version)
            changes = [f.rstrip('\n') for f in output]

        return changes

    def getbookmarks(self):
        bookmarks = {}

        # Handle local and remote branches
        remoteprefix = self.ui.config('convert', 'git.remoteprefix', 'remote')
        reftypes = [
            # (git prefix, hg prefix)
            ('refs/remotes/origin/', remoteprefix + '/'),
            ('refs/heads/', '')
        ]

        exclude = set([
            'refs/remotes/origin/HEAD',
        ])

        try:
            output, status = self.gitrunlines('show-ref')
            for line in output:
                line = line.strip()
                rev, name = line.split(None, 1)
                # Process each type of branch
                for gitprefix, hgprefix in reftypes:
                    if not name.startswith(gitprefix) or name in exclude:
                        continue
                    name = '%s%s' % (hgprefix, name[len(gitprefix):])
                    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)