Mercurial > hg
view tests/test-histedit-outgoing.t @ 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 | 5840da876235 |
children | d2a5986cb89d |
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$ cat >> $HGRCPATH <<EOF > [extensions] > histedit= > EOF $ initrepos () > { > hg init r > cd r > for x in a b c ; do > echo $x > $x > hg add $x > hg ci -m $x > done > cd .. > hg clone r r2 | grep -v updating > cd r2 > for x in d e f ; do > echo $x > $x > hg add $x > hg ci -m $x > done > cd .. > hg init r3 > cd r3 > for x in g h i ; do > echo $x > $x > hg add $x > hg ci -m $x > done > cd .. > } $ initrepos 3 files updated, 0 files merged, 0 files removed, 0 files unresolved show the edit commands offered by outgoing $ cd r2 $ HGEDITOR=cat hg histedit --outgoing ../r | grep -v comparing | grep -v searching pick 055a42cdd887 3 d pick e860deea161a 4 e pick 652413bf663e 5 f # Edit history between 055a42cdd887 and 652413bf663e # # Commits are listed from least to most recent # # Commands: # p, pick = use commit # e, edit = use commit, but stop for amending # f, fold = use commit, but combine it with the one above # d, drop = remove commit from history # m, mess = edit message without changing commit content # 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd .. show the error from unrelated repos $ cd r3 $ HGEDITOR=cat hg histedit --outgoing ../r | grep -v comparing | grep -v searching abort: repository is unrelated [1] $ cd .. show the error from unrelated repos $ cd r3 $ HGEDITOR=cat hg histedit --force --outgoing ../r comparing with ../r searching for changes warning: repository is unrelated pick 2a4042b45417 0 g pick 68c46b4927ce 1 h pick 51281e65ba79 2 i # Edit history between 2a4042b45417 and 51281e65ba79 # # Commits are listed from least to most recent # # Commands: # p, pick = use commit # e, edit = use commit, but stop for amending # f, fold = use commit, but combine it with the one above # d, drop = remove commit from history # m, mess = edit message without changing commit content # 0 files updated, 0 files merged, 0 files removed, 0 files unresolved $ cd .. test sensitivity to branch in URL: $ cd r2 $ hg -q update 2 $ hg -q branch foo $ hg commit -m 'create foo branch' $ HGEDITOR=cat hg histedit --outgoing '../r#foo' | grep -v comparing | grep -v searching pick f26599ee3441 6 create foo branch # Edit history between f26599ee3441 and f26599ee3441 # # Commits are listed from least to most recent # # Commands: # p, pick = use commit # e, edit = use commit, but stop for amending # f, fold = use commit, but combine it with the one above # d, drop = remove commit from history # m, mess = edit message without changing commit content # 0 files updated, 0 files merged, 0 files removed, 0 files unresolved test to check number of roots in outgoing revisions $ hg -q outgoing -G --template '{node|short}({branch})' '../r' @ f26599ee3441(foo) o 652413bf663e(default) | o e860deea161a(default) | o 055a42cdd887(default) $ HGEDITOR=cat hg -q histedit --outgoing '../r' abort: there are ambiguous outgoing revisions (see "hg help histedit" for more detail) [255] $ hg -q update -C 2 $ echo aa >> a $ hg -q commit -m 'another head on default' $ hg -q outgoing -G --template '{node|short}({branch})' '../r#default' @ 3879dc049647(default) o 652413bf663e(default) | o e860deea161a(default) | o 055a42cdd887(default) $ HGEDITOR=cat hg -q histedit --outgoing '../r#default' abort: there are ambiguous outgoing revisions (see "hg help histedit" for more detail) [255] $ cd ..