view mercurial/pathutil.py @ 48687:f8f2ecdde4b5

branchmap: skip obsolete revisions while computing heads

It's time to make this part of core Mercurial obsolescence-aware.

Not considering obsolete revisions when computing heads is clearly what
Mercurial should do. But there are a couple of small issues:

- Let's say tip of the repo is obsolete. There are two ways of finding tiprev
  for branchcache (both are in use): looking at input data for update() and
  looking at computed heads after update(). Previously, repo tip would be
  tiprev of the branchcache. With this patch, an obsolete revision can no
  longer be tiprev. And depending on what way we use for finding tiprev (input
  data vs computed heads) we'll get a different result. This is relevant when
  recomputing cache key from cache contents, and may lead to updating cache for
  obsolete revisions multiple times (not from scratch, because it still would
  be considered valid for a subset of revisions in the repo).

- If all commits on a branch are obsolete, the branchcache will include that
  branch, but the list of heads will be empty (that's why there's now `if not
  heads` when recomputing tiprev/tipnode from cache contents). Having an entry
  for every branch is currently required for notify extension (and
  test-notify.t to pass), because notify doesn't handle revsets in its
  subscription config very well and will throw an error if e.g. a branch
  doesn't exist.

- Cloning static HTTP repos may try to stat() a non-existent obsstore file. The
  issue is that we now care about obsolescence during clone, but statichttpvfs
  doesn't implement a stat method, so a regular vfs.stat() is used, and it
  assumes that file is local and calls os.stat().  During a clone, we're trying
  to stat() .hg/store/obsstore, but in static HTTP case we provide a literal
  URL to the obsstore file on the remote as if it were a local file path. On
  windows it actually results in a failure in test-static-http.t.

The first issue is going to be addressed in a series dedicated to making sure
branchcache is properly and timely written on disk (it wasn't perfect even
before this patch, but there aren't enough tests to demonstrate that). The
second issue will be addressed in a future patch for notify extension that will
make it not raise an exception if a branch doesn't exist. And the third one was
partially addressed in the previous patch in this series and will be properly
fixed in a future patch when this series is accepted.

filteredhash() grows a keyword argument to make sure that branchcache is also
invalidated when there are new obsolete revisions in its repo view. This way
the on-disk cache format is unchanged and compatible between versions (although
it will obviously be recomputed when switching versions before/after this patch
and the repo has obsolete revisions).

There's one test that uses plain `hg up` without arguments while updated to a
pruned commit. To make this test pass, simply return current working directory
parent. Later in this series this code will be replaced by what prune command
does: updating to the closest non-obsolete ancestor.

Test changes:

test-branch-change.t: update branch head and cache update message. The head of
default listed in hg heads is changed because revision 2 was rewritten as 7,
and 1 is the closest ancestor on the same branch, so it's the head of default
now.

The cache invalidation message appears now because of the cache hash change,
since we're now accounting for obsolete revisions. Here's some context:

"served.hidden" repo filter means everything is visible (no filtered
revisions), so before this series branch2-served.hidden file would not contain
any cache hash, only revnum and node. Now it also has a hash when there are
obsolete changesets in the repo. The command that the message appears for is
changing branch of 5 and 6, which are now obsolete, so the cache hash changes.

In general, when cache is simply out-of-date, it can be updated using the old
version as a base. But if cache hash differs, then the cache for that
particular repo filter is recomputed (at least with the current
implementation). This is what happens here.

test-obsmarker-template.t: the pull reports 2 heads changed, but after that the
repo correctly sees only 1. The new message could be better, but it's still an
improvement over the previous one where hg pull suggested merging with an
obsolete revision.

test-obsolete.t: we can see these revisions in hg log --hidden, but they
shouldn't be considered heads even with --hidden.

test-rebase-obsolete{,2}.t: there were new heads created previously after
making new orphan changesets, but they weren't detected. Now we are properly
detecting and reporting them.

test-rebase-obsolete4.t: there's only one head now because the other head is
pruned and was falsely reported before.

test-static-http.t: add obsstore to the list of requested files. This file
doesn't exist on the remotes, but clients want it anyway (they get 404). This
is fine, because there are other nonexistent files that clients request, like
.hg/bookmarks or .hg/cache/tags2-served.

Differential Revision: https://phab.mercurial-scm.org/D12097

from __future__ import absolute_import

import contextlib
import errno
import os
import posixpath
import stat

from .i18n import _
from . import (
    encoding,
    error,
    policy,
    pycompat,
    util,
)

if pycompat.TYPE_CHECKING:
    from typing import (
        Any,
        Callable,
        Iterator,
        Optional,
    )


rustdirs = policy.importrust('dirstate', 'Dirs')
parsers = policy.importmod('parsers')


def _lowerclean(s):
    # type: (bytes) -> bytes
    return encoding.hfsignoreclean(s.lower())


class pathauditor(object):
    """ensure that a filesystem path contains no banned components.
    the following properties of a path are checked:

    - ends with a directory separator
    - under top-level .hg
    - starts at the root of a windows drive
    - contains ".."

    More check are also done about the file system states:
    - traverses a symlink (e.g. a/symlink_here/b)
    - inside a nested repository (a callback can be used to approve
      some nested repositories, e.g., subrepositories)

    The file system checks are only done when 'realfs' is set to True (the
    default). They should be disable then we are auditing path for operation on
    stored history.

    If 'cached' is set to True, audited paths and sub-directories are cached.
    Be careful to not keep the cache of unmanaged directories for long because
    audited paths may be replaced with symlinks.
    """

    def __init__(self, root, callback=None, realfs=True, cached=False):
        self.audited = set()
        self.auditeddir = set()
        self.root = root
        self._realfs = realfs
        self._cached = cached
        self.callback = callback
        if os.path.lexists(root) and not util.fscasesensitive(root):
            self.normcase = util.normcase
        else:
            self.normcase = lambda x: x

    def __call__(self, path, mode=None):
        # type: (bytes, Optional[Any]) -> None
        """Check the relative path.
        path may contain a pattern (e.g. foodir/**.txt)"""

        path = util.localpath(path)
        normpath = self.normcase(path)
        if normpath in self.audited:
            return
        # AIX ignores "/" at end of path, others raise EISDIR.
        if util.endswithsep(path):
            raise error.InputError(
                _(b"path ends in directory separator: %s") % path
            )
        parts = util.splitpath(path)
        if (
            os.path.splitdrive(path)[0]
            or _lowerclean(parts[0]) in (b'.hg', b'.hg.', b'')
            or pycompat.ospardir in parts
        ):
            raise error.InputError(
                _(b"path contains illegal component: %s") % path
            )
        # Windows shortname aliases
        for p in parts:
            if b"~" in p:
                first, last = p.split(b"~", 1)
                if last.isdigit() and first.upper() in [b"HG", b"HG8B6C"]:
                    raise error.InputError(
                        _(b"path contains illegal component: %s") % path
                    )
        if b'.hg' in _lowerclean(path):
            lparts = [_lowerclean(p) for p in parts]
            for p in b'.hg', b'.hg.':
                if p in lparts[1:]:
                    pos = lparts.index(p)
                    base = os.path.join(*parts[:pos])
                    raise error.InputError(
                        _(b"path '%s' is inside nested repo %r")
                        % (path, pycompat.bytestr(base))
                    )

        normparts = util.splitpath(normpath)
        assert len(parts) == len(normparts)

        parts.pop()
        normparts.pop()
        # It's important that we check the path parts starting from the root.
        # We don't want to add "foo/bar/baz" to auditeddir before checking if
        # there's a "foo/.hg" directory. This also means we won't accidentally
        # traverse a symlink into some other filesystem (which is potentially
        # expensive to access).
        for i in range(len(parts)):
            prefix = pycompat.ossep.join(parts[: i + 1])
            normprefix = pycompat.ossep.join(normparts[: i + 1])
            if normprefix in self.auditeddir:
                continue
            if self._realfs:
                self._checkfs(prefix, path)
            if self._cached:
                self.auditeddir.add(normprefix)

        if self._cached:
            self.audited.add(normpath)

    def _checkfs(self, prefix, path):
        # type: (bytes, bytes) -> None
        """raise exception if a file system backed check fails"""
        curpath = os.path.join(self.root, prefix)
        try:
            st = os.lstat(curpath)
        except OSError as err:
            # EINVAL can be raised as invalid path syntax under win32.
            # They must be ignored for patterns can be checked too.
            if err.errno not in (errno.ENOENT, errno.ENOTDIR, errno.EINVAL):
                raise
        else:
            if stat.S_ISLNK(st.st_mode):
                msg = _(b'path %r traverses symbolic link %r') % (
                    pycompat.bytestr(path),
                    pycompat.bytestr(prefix),
                )
                raise error.Abort(msg)
            elif stat.S_ISDIR(st.st_mode) and os.path.isdir(
                os.path.join(curpath, b'.hg')
            ):
                if not self.callback or not self.callback(curpath):
                    msg = _(b"path '%s' is inside nested repo %r")
                    raise error.Abort(msg % (path, pycompat.bytestr(prefix)))

    def check(self, path):
        # type: (bytes) -> bool
        try:
            self(path)
            return True
        except (OSError, error.Abort):
            return False

    @contextlib.contextmanager
    def cached(self):
        if self._cached:
            yield
        else:
            try:
                self._cached = True
                yield
            finally:
                self.audited.clear()
                self.auditeddir.clear()
                self._cached = False


def canonpath(root, cwd, myname, auditor=None):
    # type: (bytes, bytes, bytes, Optional[pathauditor]) -> bytes
    """return the canonical path of myname, given cwd and root

    >>> def check(root, cwd, myname):
    ...     a = pathauditor(root, realfs=False)
    ...     try:
    ...         return canonpath(root, cwd, myname, a)
    ...     except error.Abort:
    ...         return 'aborted'
    >>> def unixonly(root, cwd, myname, expected='aborted'):
    ...     if pycompat.iswindows:
    ...         return expected
    ...     return check(root, cwd, myname)
    >>> def winonly(root, cwd, myname, expected='aborted'):
    ...     if not pycompat.iswindows:
    ...         return expected
    ...     return check(root, cwd, myname)
    >>> winonly(b'd:\\\\repo', b'c:\\\\dir', b'filename')
    'aborted'
    >>> winonly(b'c:\\\\repo', b'c:\\\\dir', b'filename')
    'aborted'
    >>> winonly(b'c:\\\\repo', b'c:\\\\', b'filename')
    'aborted'
    >>> winonly(b'c:\\\\repo', b'c:\\\\', b'repo\\\\filename',
    ...         b'filename')
    'filename'
    >>> winonly(b'c:\\\\repo', b'c:\\\\repo', b'filename', b'filename')
    'filename'
    >>> winonly(b'c:\\\\repo', b'c:\\\\repo\\\\subdir', b'filename',
    ...         b'subdir/filename')
    'subdir/filename'
    >>> unixonly(b'/repo', b'/dir', b'filename')
    'aborted'
    >>> unixonly(b'/repo', b'/', b'filename')
    'aborted'
    >>> unixonly(b'/repo', b'/', b'repo/filename', b'filename')
    'filename'
    >>> unixonly(b'/repo', b'/repo', b'filename', b'filename')
    'filename'
    >>> unixonly(b'/repo', b'/repo/subdir', b'filename', b'subdir/filename')
    'subdir/filename'
    """
    if util.endswithsep(root):
        rootsep = root
    else:
        rootsep = root + pycompat.ossep
    name = myname
    if not os.path.isabs(name):
        name = os.path.join(root, cwd, name)
    name = os.path.normpath(name)
    if auditor is None:
        auditor = pathauditor(root)
    if name != rootsep and name.startswith(rootsep):
        name = name[len(rootsep) :]
        auditor(name)
        return util.pconvert(name)
    elif name == root:
        return b''
    else:
        # Determine whether `name' is in the hierarchy at or beneath `root',
        # by iterating name=dirname(name) until that causes no change (can't
        # check name == '/', because that doesn't work on windows). The list
        # `rel' holds the reversed list of components making up the relative
        # file name we want.
        rel = []
        while True:
            try:
                s = util.samefile(name, root)
            except OSError:
                s = False
            if s:
                if not rel:
                    # name was actually the same as root (maybe a symlink)
                    return b''
                rel.reverse()
                name = os.path.join(*rel)
                auditor(name)
                return util.pconvert(name)
            dirname, basename = util.split(name)
            rel.append(basename)
            if dirname == name:
                break
            name = dirname

        # A common mistake is to use -R, but specify a file relative to the repo
        # instead of cwd.  Detect that case, and provide a hint to the user.
        hint = None
        try:
            if cwd != root:
                canonpath(root, root, myname, auditor)
                relpath = util.pathto(root, cwd, b'')
                if relpath.endswith(pycompat.ossep):
                    relpath = relpath[:-1]
                hint = _(b"consider using '--cwd %s'") % relpath
        except error.Abort:
            pass

        raise error.Abort(
            _(b"%s not under root '%s'") % (myname, root), hint=hint
        )


def normasprefix(path):
    # type: (bytes) -> bytes
    """normalize the specified path as path prefix

    Returned value can be used safely for "p.startswith(prefix)",
    "p[len(prefix):]", and so on.

    For efficiency, this expects "path" argument to be already
    normalized by "os.path.normpath", "os.path.realpath", and so on.

    See also issue3033 for detail about need of this function.

    >>> normasprefix(b'/foo/bar').replace(pycompat.ossep, b'/')
    '/foo/bar/'
    >>> normasprefix(b'/').replace(pycompat.ossep, b'/')
    '/'
    """
    d, p = os.path.splitdrive(path)
    if len(p) != len(pycompat.ossep):
        return path + pycompat.ossep
    else:
        return path


def finddirs(path):
    # type: (bytes) -> Iterator[bytes]
    pos = path.rfind(b'/')
    while pos != -1:
        yield path[:pos]
        pos = path.rfind(b'/', 0, pos)
    yield b''


class dirs(object):
    '''a multiset of directory names from a set of file paths'''

    def __init__(self, map, only_tracked=False):
        """
        a dict map indicates a dirstate while a list indicates a manifest
        """
        self._dirs = {}
        addpath = self.addpath
        if isinstance(map, dict) and only_tracked:
            for f, s in pycompat.iteritems(map):
                if s.state != b'r':
                    addpath(f)
        elif only_tracked:
            msg = b"`only_tracked` is only supported with a dict source"
            raise error.ProgrammingError(msg)
        else:
            for f in map:
                addpath(f)

    def addpath(self, path):
        # type: (bytes) -> None
        dirs = self._dirs
        for base in finddirs(path):
            if base.endswith(b'/'):
                raise ValueError(
                    "found invalid consecutive slashes in path: %r" % base
                )
            if base in dirs:
                dirs[base] += 1
                return
            dirs[base] = 1

    def delpath(self, path):
        # type: (bytes) -> None
        dirs = self._dirs
        for base in finddirs(path):
            if dirs[base] > 1:
                dirs[base] -= 1
                return
            del dirs[base]

    def __iter__(self):
        return iter(self._dirs)

    def __contains__(self, d):
        # type: (bytes) -> bool
        return d in self._dirs


if util.safehasattr(parsers, 'dirs'):
    dirs = parsers.dirs

if rustdirs is not None:
    dirs = rustdirs


# forward two methods from posixpath that do what we need, but we'd
# rather not let our internals know that we're thinking in posix terms
# - instead we'll let them be oblivious.
join = posixpath.join
dirname = posixpath.dirname  # type: Callable[[bytes], bytes]