view hgext/schemes.py @ 20742:3681de20b0a7

parsers: fail fast if Python has wrong minor version (issue4110) This change causes an informative ImportError to be raised when importing the parsers extension module if the minor version of the currently-running Python interpreter doesn't match that of the Python used when compiling the extension module. This change also exposes a parsers.versionerrortext constant in the C implementation of the module. Its presence can be used to determine whether this behavior is present in a version of the module. The value of the constant is the leading text of the ImportError raised and is set to "Python minor version mismatch". Here is an example of what the new error looks like: Traceback (most recent call last): File "test.py", line 1, in <module> import mercurial.parsers ImportError: Python minor version mismatch: The Mercurial extension modules were compiled with Python 2.7.6, but Mercurial is currently using Python with sys.hexversion=33883888: Python 2.5.6 (r256:88840, Nov 18 2012, 05:37:10) [GCC 4.2.1 Compatible Apple Clang 4.1 ((tags/Apple/clang-421.11.66))] at: /opt/local/Library/Frameworks/Python.framework/Versions/2.5/Resources/ Python.app/Contents/MacOS/Python The reason for raising an error in this scenario is that Python's C API is known not to be compatible from minor version to minor version, even if sys.api_version is the same. See for example this Python bug report about incompatibilities between 2.5 and 2.6+: http://bugs.python.org/issue8118 These incompatibilities can cause Mercurial to break in mysterious, unforeseen ways. For example, when Mercurial compiled with Python 2.7 was run with 2.5, the following crash occurred when running "hg status": http://bz.selenic.com/show_bug.cgi?id=4110 After this crash was fixed, running with Python 2.5 no longer crashes, but the following puzzling behavior still occurs: $ hg status ... File ".../mercurial/changelog.py", line 123, in __init__ revlog.revlog.__init__(self, opener, "00changelog.i") File ".../mercurial/revlog.py", line 251, in __init__ d = self._io.parseindex(i, self._inline) File ".../mercurial/revlog.py", line 158, in parseindex index, cache = parsers.parse_index2(data, inline) TypeError: data is not a string which can be reproduced more simply with: import mercurial.parsers as parsers parsers.parse_index2("", True) Both the crash and the TypeError occurred because the Python C API's PyString_Check() returns the wrong value when the C header files from Python 2.7 are run with Python 2.5. This is an example of an incompatibility of the sort mentioned in the Python bug report above. Failing fast with an informative error message results in a better user experience in cases like the above. The information in the ImportError also simplifies troubleshooting for those on Mercurial mailing lists, the bug tracker, etc. This patch only adds the version check to parsers.c, which is sufficient to affect command-line commands like "hg status" and "hg summary". An idea for a future improvement is to move the version-checking C code to a more central location, and have it run when importing all Mercurial extension modules and not just parsers.c.
author Chris Jerdonek <chris.jerdonek@gmail.com>
date Wed, 04 Dec 2013 20:38:27 -0800
parents b52404a914a9
children 80c5b2666a96
line wrap: on
line source

# Copyright 2009, Alexander Solovyov <piranha@piranha.org.ua>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

"""extend schemes with shortcuts to repository swarms

This extension allows you to specify shortcuts for parent URLs with a
lot of repositories to act like a scheme, for example::

  [schemes]
  py = http://code.python.org/hg/

After that you can use it like::

  hg clone py://trunk/

Additionally there is support for some more complex schemas, for
example used by Google Code::

  [schemes]
  gcode = http://{1}.googlecode.com/hg/

The syntax is taken from Mercurial templates, and you have unlimited
number of variables, starting with ``{1}`` and continuing with
``{2}``, ``{3}`` and so on. This variables will receive parts of URL
supplied, split by ``/``. Anything not specified as ``{part}`` will be
just appended to an URL.

For convenience, the extension adds these schemes by default::

  [schemes]
  py = http://hg.python.org/
  bb = https://bitbucket.org/
  bb+ssh = ssh://hg@bitbucket.org/
  gcode = https://{1}.googlecode.com/hg/
  kiln = https://{1}.kilnhg.com/Repo/

You can override a predefined scheme by defining a new scheme with the
same name.
"""

import os, re
from mercurial import extensions, hg, templater, util
from mercurial.i18n import _

testedwith = 'internal'


class ShortRepository(object):
    def __init__(self, url, scheme, templater):
        self.scheme = scheme
        self.templater = templater
        self.url = url
        try:
            self.parts = max(map(int, re.findall(r'\{(\d+)\}', self.url)))
        except ValueError:
            self.parts = 0

    def __repr__(self):
        return '<ShortRepository: %s>' % self.scheme

    def instance(self, ui, url, create):
        # Should this use the util.url class, or is manual parsing better?
        try:
            url = url.split('://', 1)[1]
        except IndexError:
            raise util.Abort(_("no '://' in scheme url '%s'") % url)
        parts = url.split('/', self.parts)
        if len(parts) > self.parts:
            tail = parts[-1]
            parts = parts[:-1]
        else:
            tail = ''
        context = dict((str(i + 1), v) for i, v in enumerate(parts))
        url = ''.join(self.templater.process(self.url, context)) + tail
        return hg._peerlookup(url).instance(ui, url, create)

def hasdriveletter(orig, path):
    if path:
        for scheme in schemes:
            if path.startswith(scheme + ':'):
                return False
    return orig(path)

schemes = {
    'py': 'http://hg.python.org/',
    'bb': 'https://bitbucket.org/',
    'bb+ssh': 'ssh://hg@bitbucket.org/',
    'gcode': 'https://{1}.googlecode.com/hg/',
    'kiln': 'https://{1}.kilnhg.com/Repo/'
    }

def extsetup(ui):
    schemes.update(dict(ui.configitems('schemes')))
    t = templater.engine(lambda x: x)
    for scheme, url in schemes.items():
        if (os.name == 'nt' and len(scheme) == 1 and scheme.isalpha()
            and os.path.exists('%s:\\' % scheme)):
            raise util.Abort(_('custom scheme %s:// conflicts with drive '
                               'letter %s:\\\n') % (scheme, scheme.upper()))
        hg.schemes[scheme] = ShortRepository(url, scheme, t)

    extensions.wrapfunction(util, 'hasdriveletter', hasdriveletter)