hgext/git/dirstate.py

git: correctly handle p1() on dirstate when underlying git repo is empty

This shows up in my next change, which ends up making an empty git
repo and then running hg.

Differential Revision: https://phab.mercurial-scm.org/D8271

from __future__ import absolute_import

import contextlib
import errno
import os

from mercurial import (
    error,
    extensions,
    match as matchmod,
    node as nodemod,
    pycompat,
    scmutil,
    util,
)
from mercurial.interfaces import (
    dirstate as intdirstate,
    util as interfaceutil,
)

from . import gitutil

pygit2 = gitutil.get_pygit2()


def readpatternfile(orig, filepath, warn, sourceinfo=False):
    if not (b'info/exclude' in filepath or filepath.endswith(b'.gitignore')):
        return orig(filepath, warn, sourceinfo=False)
    result = []
    warnings = []
    with open(filepath, b'rb') as fp:
        for l in fp:
            l = l.strip()
            if not l or l.startswith(b'#'):
                continue
            if l.startswith(b'!'):
                warnings.append(b'unsupported ignore pattern %s' % l)
                continue
            if l.startswith(b'/'):
                result.append(b'rootglob:' + l[1:])
            else:
                result.append(b'relglob:' + l)
    return result, warnings


extensions.wrapfunction(matchmod, b'readpatternfile', readpatternfile)


_STATUS_MAP = {}
if pygit2:
    _STATUS_MAP = {
        pygit2.GIT_STATUS_CONFLICTED: b'm',
        pygit2.GIT_STATUS_CURRENT: b'n',
        pygit2.GIT_STATUS_IGNORED: b'?',
        pygit2.GIT_STATUS_INDEX_DELETED: b'r',
        pygit2.GIT_STATUS_INDEX_MODIFIED: b'n',
        pygit2.GIT_STATUS_INDEX_NEW: b'a',
        pygit2.GIT_STATUS_INDEX_RENAMED: b'a',
        pygit2.GIT_STATUS_INDEX_TYPECHANGE: b'n',
        pygit2.GIT_STATUS_WT_DELETED: b'r',
        pygit2.GIT_STATUS_WT_MODIFIED: b'n',
        pygit2.GIT_STATUS_WT_NEW: b'?',
        pygit2.GIT_STATUS_WT_RENAMED: b'a',
        pygit2.GIT_STATUS_WT_TYPECHANGE: b'n',
        pygit2.GIT_STATUS_WT_UNREADABLE: b'?',
        pygit2.GIT_STATUS_INDEX_MODIFIED | pygit2.GIT_STATUS_WT_MODIFIED: 'm',
    }


@interfaceutil.implementer(intdirstate.idirstate)
class gitdirstate(object):
    def __init__(self, ui, root, gitrepo):
        self._ui = ui
        self._root = os.path.dirname(root)
        self.git = gitrepo
        self._plchangecallbacks = {}

    def p1(self):
        try:
            return self.git.head.peel().id.raw
        except pygit2.GitError:
            # Typically happens when peeling HEAD fails, as in an
            # empty repository.
            return nodemod.nullid

    def p2(self):
        # TODO: MERGE_HEAD? something like that, right?
        return nodemod.nullid

    def setparents(self, p1, p2=nodemod.nullid):
        assert p2 == nodemod.nullid, b'TODO merging support'
        self.git.head.set_target(gitutil.togitnode(p1))

    @util.propertycache
    def identity(self):
        return util.filestat.frompath(
            os.path.join(self._root, b'.git', b'index')
        )

    def branch(self):
        return b'default'

    def parents(self):
        # TODO how on earth do we find p2 if a merge is in flight?
        return self.p1(), nodemod.nullid

    def __iter__(self):
        return (pycompat.fsencode(f.path) for f in self.git.index)

    def items(self):
        for ie in self.git.index:
            yield ie.path, None  # value should be a dirstatetuple

    # py2,3 compat forward
    iteritems = items

    def __getitem__(self, filename):
        try:
            gs = self.git.status_file(filename)
        except KeyError:
            return b'?'
        return _STATUS_MAP[gs]

    def __contains__(self, filename):
        try:
            gs = self.git.status_file(filename)
            return _STATUS_MAP[gs] != b'?'
        except KeyError:
            return False

    def status(self, match, subrepos, ignored, clean, unknown):
        # TODO handling of clean files - can we get that from git.status()?
        modified, added, removed, deleted, unknown, ignored, clean = (
            [],
            [],
            [],
            [],
            [],
            [],
            [],
        )
        gstatus = self.git.status()
        for path, status in gstatus.items():
            path = pycompat.fsencode(path)
            if status == pygit2.GIT_STATUS_IGNORED:
                if path.endswith(b'/'):
                    continue
                ignored.append(path)
            elif status in (
                pygit2.GIT_STATUS_WT_MODIFIED,
                pygit2.GIT_STATUS_INDEX_MODIFIED,
                pygit2.GIT_STATUS_WT_MODIFIED
                | pygit2.GIT_STATUS_INDEX_MODIFIED,
            ):
                modified.append(path)
            elif status == pygit2.GIT_STATUS_INDEX_NEW:
                added.append(path)
            elif status == pygit2.GIT_STATUS_WT_NEW:
                unknown.append(path)
            elif status == pygit2.GIT_STATUS_WT_DELETED:
                deleted.append(path)
            elif status == pygit2.GIT_STATUS_INDEX_DELETED:
                removed.append(path)
            else:
                raise error.Abort(
                    b'unhandled case: status for %r is %r' % (path, status)
                )

        # TODO are we really always sure of status here?
        return (
            False,
            scmutil.status(
                modified, added, removed, deleted, unknown, ignored, clean
            ),
        )

    def flagfunc(self, buildfallback):
        # TODO we can do better
        return buildfallback()

    def getcwd(self):
        # TODO is this a good way to do this?
        return os.path.dirname(
            os.path.dirname(pycompat.fsencode(self.git.path))
        )

    def normalize(self, path):
        normed = util.normcase(path)
        assert normed == path, b"TODO handling of case folding: %s != %s" % (
            normed,
            path,
        )
        return path

    @property
    def _checklink(self):
        return util.checklink(os.path.dirname(pycompat.fsencode(self.git.path)))

    def copies(self):
        # TODO support copies?
        return {}

    # # TODO what the heck is this
    _filecache = set()

    def pendingparentchange(self):
        # TODO: we need to implement the context manager bits and
        # correctly stage/revert index edits.
        return False

    def write(self, tr):
        # TODO: call parent change callbacks

        if tr:

            def writeinner(category):
                self.git.index.write()

            tr.addpending(b'gitdirstate', writeinner)
        else:
            self.git.index.write()

    def pathto(self, f, cwd=None):
        if cwd is None:
            cwd = self.getcwd()
        # TODO core dirstate does something about slashes here
        assert isinstance(f, bytes)
        r = util.pathto(self._root, cwd, f)
        return r

    def matches(self, match):
        for x in self.git.index:
            p = pycompat.fsencode(x.path)
            if match(p):
                yield p

    def normal(self, f, parentfiledata=None):
        """Mark a file normal and clean."""
        # TODO: for now we just let libgit2 re-stat the file. We can
        # clearly do better.

    def normallookup(self, f):
        """Mark a file normal, but possibly dirty."""
        # TODO: for now we just let libgit2 re-stat the file. We can
        # clearly do better.

    def walk(self, match, subrepos, unknown, ignored, full=True):
        # TODO: we need to use .status() and not iterate the index,
        # because the index doesn't force a re-walk and so `hg add` of
        # a new file without an intervening call to status will
        # silently do nothing.
        r = {}
        cwd = self.getcwd()
        for path, status in self.git.status().items():
            if path.startswith('.hg/'):
                continue
            path = pycompat.fsencode(path)
            if not match(path):
                continue
            # TODO construct the stat info from the status object?
            try:
                s = os.stat(os.path.join(cwd, path))
            except OSError as e:
                if e.errno != errno.ENOENT:
                    raise
                continue
            r[path] = s
        return r

    def savebackup(self, tr, backupname):
        # TODO: figure out a strategy for saving index backups.
        pass

    def restorebackup(self, tr, backupname):
        # TODO: figure out a strategy for saving index backups.
        pass

    def add(self, f):
        self.git.index.add(pycompat.fsdecode(f))

    def drop(self, f):
        self.git.index.remove(pycompat.fsdecode(f))

    def remove(self, f):
        self.git.index.remove(pycompat.fsdecode(f))

    def copied(self, path):
        # TODO: track copies?
        return None

    @contextlib.contextmanager
    def parentchange(self):
        # TODO: track this maybe?
        yield

    def addparentchangecallback(self, category, callback):
        # TODO: should this be added to the dirstate interface?
        self._plchangecallbacks[category] = callback

    def clearbackup(self, tr, backupname):
        # TODO
        pass