Mercurial > hg
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)