view mercurial/narrowspec.py @ 40093:726cfc47f17a

contrib: add an utility module to parse test scripts

This patch centralizes the logic to pick up code fragments embedded in
*.t script, in order to:

  - apply checking with patterns in check-code.py on such embedded
    code fragments

    Now, check-code.py completely ignores embedded code
    fragments. I'll post another patch series to check them.

  - replace similar code path in contrib/import-checker.py

    Current import-checker.py has problems below. Fixing each of them
    is a little difficult, because parsing logic and pattern strings
    are tightly coupled.

    - overlook (or mis-detect) the end of inline script in doctest
      style

      8a8dd6e4a97a fixed a part of this issue, but not enough.

    - it overlooks inline script in doctest style at the end of file
      (and ignores invalid un-closed heredoc at the end of file, too)

    - it overlooks code fragment in styles below
      - "python <<EOF" (heredoc should be "cat > file <<EOF" style)
      - "cat > foobar.py << ANYLIMIT" (limit mark should be "EOF")
      - "cat << EOF > foobar.py" (filename should be placed before limit mark)
      - "cat >> foobar.py << EOF" (appending is ignored)

    - it is not extensible for other than python code fragments
      (e.g. shell script, hgrc file, and so on)

This new module can detect python code fragments in styles below:

  - inline script in doctest style (starting by "  >>> " line)
  - python invocation with heredoc script ("python <<EOF")
  - python script in heredoc style (redirected into ".py" file)

As an example of extensibility of new module, this patch also contains
implementation to pick up code fragment below. This will be useful to
add additional restriction for them, for example.

  - shell script in heredoc style (redirected into ".sh" file)
  - hgrc configuration in heredoc style (redirected into hgrc or $HGRCPATH)

# narrowspec.py - methods for working with a narrow view of a repository
#
# Copyright 2017 Google, Inc.
#
# 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 errno

from .i18n import _
from . import (
    error,
    match as matchmod,
    repository,
    sparse,
    util,
)

FILENAME = 'narrowspec'

# Pattern prefixes that are allowed in narrow patterns. This list MUST
# only contain patterns that are fast and safe to evaluate. Keep in mind
# that patterns are supplied by clients and executed on remote servers
# as part of wire protocol commands. That means that changes to this
# data structure influence the wire protocol and should not be taken
# lightly - especially removals.
VALID_PREFIXES = (
    b'path:',
    b'rootfilesin:',
)

def normalizesplitpattern(kind, pat):
    """Returns the normalized version of a pattern and kind.

    Returns a tuple with the normalized kind and normalized pattern.
    """
    pat = pat.rstrip('/')
    _validatepattern(pat)
    return kind, pat

def _numlines(s):
    """Returns the number of lines in s, including ending empty lines."""
    # We use splitlines because it is Unicode-friendly and thus Python 3
    # compatible. However, it does not count empty lines at the end, so trick
    # it by adding a character at the end.
    return len((s + 'x').splitlines())

def _validatepattern(pat):
    """Validates the pattern and aborts if it is invalid.

    Patterns are stored in the narrowspec as newline-separated
    POSIX-style bytestring paths. There's no escaping.
    """

    # We use newlines as separators in the narrowspec file, so don't allow them
    # in patterns.
    if _numlines(pat) > 1:
        raise error.Abort(_('newlines are not allowed in narrowspec paths'))

    components = pat.split('/')
    if '.' in components or '..' in components:
        raise error.Abort(_('"." and ".." are not allowed in narrowspec paths'))

def normalizepattern(pattern, defaultkind='path'):
    """Returns the normalized version of a text-format pattern.

    If the pattern has no kind, the default will be added.
    """
    kind, pat = matchmod._patsplit(pattern, defaultkind)
    return '%s:%s' % normalizesplitpattern(kind, pat)

def parsepatterns(pats):
    """Parses an iterable of patterns into a typed pattern set.

    Patterns are assumed to be ``path:`` if no prefix is present.
    For safety and performance reasons, only some prefixes are allowed.
    See ``validatepatterns()``.

    This function should be used on patterns that come from the user to
    normalize and validate them to the internal data structure used for
    representing patterns.
    """
    res = {normalizepattern(orig) for orig in pats}
    validatepatterns(res)
    return res

def validatepatterns(pats):
    """Validate that patterns are in the expected data structure and format.

    And that is a set of normalized patterns beginning with ``path:`` or
    ``rootfilesin:``.

    This function should be used to validate internal data structures
    and patterns that are loaded from sources that use the internal,
    prefixed pattern representation (but can't necessarily be fully trusted).
    """
    if not isinstance(pats, set):
        raise error.ProgrammingError('narrow patterns should be a set; '
                                     'got %r' % pats)

    for pat in pats:
        if not pat.startswith(VALID_PREFIXES):
            # Use a Mercurial exception because this can happen due to user
            # bugs (e.g. manually updating spec file).
            raise error.Abort(_('invalid prefix on narrow pattern: %s') % pat,
                              hint=_('narrow patterns must begin with one of '
                                     'the following: %s') %
                                   ', '.join(VALID_PREFIXES))

def format(includes, excludes):
    output = '[include]\n'
    for i in sorted(includes - excludes):
        output += i + '\n'
    output += '[exclude]\n'
    for e in sorted(excludes):
        output += e + '\n'
    return output

def match(root, include=None, exclude=None):
    if not include:
        # Passing empty include and empty exclude to matchmod.match()
        # gives a matcher that matches everything, so explicitly use
        # the nevermatcher.
        return matchmod.never(root, '')
    return matchmod.match(root, '', [], include=include or [],
                          exclude=exclude or [])

def load(repo):
    try:
        spec = repo.svfs.read(FILENAME)
    except IOError as e:
        # Treat "narrowspec does not exist" the same as "narrowspec file exists
        # and is empty".
        if e.errno == errno.ENOENT:
            return set(), set()
        raise
    # maybe we should care about the profiles returned too
    includepats, excludepats, profiles = sparse.parseconfig(repo.ui, spec,
                                                            'narrow')
    if profiles:
        raise error.Abort(_("including other spec files using '%include' is not"
                            " supported in narrowspec"))

    validatepatterns(includepats)
    validatepatterns(excludepats)

    return includepats, excludepats

def save(repo, includepats, excludepats):
    validatepatterns(includepats)
    validatepatterns(excludepats)
    spec = format(includepats, excludepats)
    repo.svfs.write(FILENAME, spec)

def savebackup(repo, backupname):
    if repository.NARROW_REQUIREMENT not in repo.requirements:
        return
    vfs = repo.vfs
    vfs.tryunlink(backupname)
    util.copyfile(repo.svfs.join(FILENAME), vfs.join(backupname), hardlink=True)

def restorebackup(repo, backupname):
    if repository.NARROW_REQUIREMENT not in repo.requirements:
        return
    util.rename(repo.vfs.join(backupname), repo.svfs.join(FILENAME))

def clearbackup(repo, backupname):
    if repository.NARROW_REQUIREMENT not in repo.requirements:
        return
    repo.vfs.unlink(backupname)

def restrictpatterns(req_includes, req_excludes, repo_includes, repo_excludes):
    r""" Restricts the patterns according to repo settings,
    results in a logical AND operation

    :param req_includes: requested includes
    :param req_excludes: requested excludes
    :param repo_includes: repo includes
    :param repo_excludes: repo excludes
    :return: include patterns, exclude patterns, and invalid include patterns.

    >>> restrictpatterns({'f1','f2'}, {}, ['f1'], [])
    (set(['f1']), {}, [])
    >>> restrictpatterns({'f1'}, {}, ['f1','f2'], [])
    (set(['f1']), {}, [])
    >>> restrictpatterns({'f1/fc1', 'f3/fc3'}, {}, ['f1','f2'], [])
    (set(['f1/fc1']), {}, [])
    >>> restrictpatterns({'f1_fc1'}, {}, ['f1','f2'], [])
    ([], set(['path:.']), [])
    >>> restrictpatterns({'f1/../f2/fc2'}, {}, ['f1','f2'], [])
    (set(['f2/fc2']), {}, [])
    >>> restrictpatterns({'f1/../f3/fc3'}, {}, ['f1','f2'], [])
    ([], set(['path:.']), [])
    >>> restrictpatterns({'f1/$non_exitent_var'}, {}, ['f1','f2'], [])
    (set(['f1/$non_exitent_var']), {}, [])
    """
    res_excludes = set(req_excludes)
    res_excludes.update(repo_excludes)
    invalid_includes = []
    if not req_includes:
        res_includes = set(repo_includes)
    elif 'path:.' not in repo_includes:
        res_includes = []
        for req_include in req_includes:
            req_include = util.expandpath(util.normpath(req_include))
            if req_include in repo_includes:
                res_includes.append(req_include)
                continue
            valid = False
            for repo_include in repo_includes:
                if req_include.startswith(repo_include + '/'):
                    valid = True
                    res_includes.append(req_include)
                    break
            if not valid:
                invalid_includes.append(req_include)
        if len(res_includes) == 0:
            res_excludes = {'path:.'}
        else:
            res_includes = set(res_includes)
    else:
        res_includes = set(req_includes)
    return res_includes, res_excludes, invalid_includes