fileset: add a lightweight file filtering language
This patch was inspired by one that Jun Wu authored for the fb-experimental
repo, to avoid using matcher for efficiency[1]. We want a way to specify what
files will be converted to LFS at commit time. And per discussion, we also want
to specify what files to skip, text diff, or merge in another config option.
The current `lfs.threshold` config option could not satisfy complex needs. I'm
putting it in a core package because Augie floated the idea of also using it for
narrow and sparse.
Yuya suggested farming out to fileset.parse(), which added support for more
symbols. The only fileset element not supported here is 'negate'. (List isn't
supported by filesets either.) I also changed the 'always' token to the 'all()'
predicate for consistency, and introduced 'none()' to improve readability in a
future tracked file based config. The extension operator was changed from '.'
to '**', to match how recursive path globs are specified. Finally, I changed
the path matcher from '/' to 'path:' at Yuya's suggestion, for consistency with
matcher. Unfortunately, ':' is currently reserved in filesets, so this has to
be quoted to be processed as a string instead of a symbol[2]. We should
probably revisit that, because it's seriously ugly. But it's only used by an
experimental extension, and I think using a file based config for LFS may drive
some more tweaks, so I'm settling for this for now.
I reserved all of the glob characters in fileset except '.' and '_' for the
extension test because those are likely valid extension characters.
Sample filter settings:
all() # everything
size(">20MB") # larger than 20MB
!**.txt # except for .txt files
**.zip | **.tar.gz | **.7z # some types of compressed files
"path:bin" # files under "bin" in the project root
[1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-December/109387.html
[2] https://www.mercurial-scm.org/pipermail/mercurial-devel/2018-January/109729.html
from __future__ import absolute_import
import errno
import os
import posixpath
import stat
from .i18n import _
from . import (
encoding,
error,
pycompat,
util,
)
def _lowerclean(s):
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):
'''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.Abort(_("path ends in directory separator: %s") % path)
parts = util.splitpath(path)
if (os.path.splitdrive(path)[0]
or _lowerclean(parts[0]) in ('.hg', '.hg.', '')
or os.pardir in parts):
raise error.Abort(_("path contains illegal component: %s") % path)
# Windows shortname aliases
for p in parts:
if "~" in p:
first, last = p.split("~", 1)
if last.isdigit() and first.upper() in ["HG", "HG8B6C"]:
raise error.Abort(_("path contains illegal component: %s")
% path)
if '.hg' in _lowerclean(path):
lparts = [_lowerclean(p.lower()) for p in parts]
for p in '.hg', '.hg.':
if p in lparts[1:]:
pos = lparts.index(p)
base = os.path.join(*parts[:pos])
raise error.Abort(_("path '%s' is inside nested repo %r")
% (path, base))
normparts = util.splitpath(normpath)
assert len(parts) == len(normparts)
parts.pop()
normparts.pop()
prefixes = []
# It's important that we check the path parts starting from the root.
# This 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)
prefixes.append(normprefix)
if self._cached:
self.audited.add(normpath)
# only add prefixes to the cache after checking everything: we don't
# want to add "foo/bar/baz" before checking if there's a "foo/.hg"
self.auditeddir.update(prefixes)
def _checkfs(self, prefix, path):
"""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 = _('path %r traverses symbolic link %r') % (path, prefix)
raise error.Abort(msg)
elif (stat.S_ISDIR(st.st_mode) and
os.path.isdir(os.path.join(curpath, '.hg'))):
if not self.callback or not self.callback(curpath):
msg = _("path '%s' is inside nested repo %r")
raise error.Abort(msg % (path, prefix))
def check(self, path):
try:
self(path)
return True
except (OSError, error.Abort):
return False
def canonpath(root, cwd, myname, auditor=None):
'''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 ''
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 ''
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, '')
if relpath[-1] == pycompat.ossep:
relpath = relpath[:-1]
hint = (_("consider using '--cwd %s'") % relpath)
except error.Abort:
pass
raise error.Abort(_("%s not under root '%s'") % (myname, root),
hint=hint)
def normasprefix(path):
'''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
# 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