Mercurial > hg
view tests/test-largefiles-cache.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 | ea005e754c9c |
children | 7731a2281cf0 |
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Create user cache directory $ USERCACHE=`pwd`/cache; export USERCACHE $ cat <<EOF >> ${HGRCPATH} > [extensions] > hgext.largefiles= > [largefiles] > usercache=${USERCACHE} > EOF $ mkdir -p ${USERCACHE} Create source repo, and commit adding largefile. $ hg init src $ cd src $ echo large > large $ hg add --large large $ hg commit -m 'add largefile' $ hg rm large $ hg commit -m 'branchhead without largefile' $ hg up -qr 0 $ cd .. Discard all cached largefiles in USERCACHE $ rm -rf ${USERCACHE} Create mirror repo, and pull from source without largefile: "pull" is used instead of "clone" for suppression of (1) updating to tip (= cahcing largefile from source repo), and (2) recording source repo as "default" path in .hg/hgrc. $ hg init mirror $ cd mirror $ hg pull ../src pulling from ../src requesting all changes adding changesets adding manifests adding file changes added 2 changesets with 1 changes to 1 files (run 'hg update' to get a working copy) Update working directory to "tip", which requires largefile("large"), but there is no cache file for it. So, hg must treat it as "missing"(!) file. $ hg update -r0 getting changed largefiles large: largefile 7f7097b041ccf68cc5561e9600da4655d21c6d18 not available from file:/*/$TESTTMP/mirror (glob) 0 largefiles updated, 0 removed 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg status ! large Update working directory to null: this cleanup .hg/largefiles/dirstate $ hg update null getting changed largefiles 0 largefiles updated, 0 removed 0 files updated, 0 files merged, 1 files removed, 0 files unresolved Update working directory to tip, again. $ hg update -r0 getting changed largefiles large: largefile 7f7097b041ccf68cc5561e9600da4655d21c6d18 not available from file:/*/$TESTTMP/mirror (glob) 0 largefiles updated, 0 removed 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg status ! large $ cd .. Verify that largefiles from pulled branchheads are fetched, also to an empty repo $ hg init mirror2 $ hg -R mirror2 pull src -r0 pulling from src adding changesets adding manifests adding file changes added 1 changesets with 1 changes to 1 files (run 'hg update' to get a working copy) #if unix-permissions Portable way to print file permissions: $ cat > ls-l.py <<EOF > #!/usr/bin/env python > import sys, os > path = sys.argv[1] > print '%03o' % (os.lstat(path).st_mode & 0777) > EOF $ chmod +x ls-l.py Test that files in .hg/largefiles inherit mode from .hg/store, not from file in working copy: $ cd src $ chmod 750 .hg/store $ chmod 660 large $ echo change >> large $ hg commit -m change created new head $ ../ls-l.py .hg/largefiles/e151b474069de4ca6898f67ce2f2a7263adf8fea 640 Test permission of with files in .hg/largefiles created by update: $ cd ../mirror $ rm -r "$USERCACHE" .hg/largefiles # avoid links $ chmod 750 .hg/store $ hg pull ../src --update -q $ ../ls-l.py .hg/largefiles/e151b474069de4ca6898f67ce2f2a7263adf8fea 640 Test permission of files created by push: $ hg serve -R ../src -d -p $HGPORT --pid-file hg.pid \ > --config "web.allow_push=*" --config web.push_ssl=no $ cat hg.pid >> $DAEMON_PIDS $ echo change >> large $ hg commit -m change $ rm -r "$USERCACHE" $ hg push -q http://localhost:$HGPORT/ $ ../ls-l.py ../src/.hg/largefiles/b734e14a0971e370408ab9bce8d56d8485e368a9 640 $ cd .. #endif