Mercurial > hg
view tests/test-hgweb-removed.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 | 544848ef65f2 |
| children | 7a9cbb315d84 |
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$ "$TESTDIR/hghave" serve || exit 80 setting up repo $ hg init test $ cd test $ echo a > a $ hg ci -Ama adding a $ hg rm a $ hg ci -mdel set up hgweb $ hg serve -n test -p $HGPORT -d --pid-file=hg.pid -A access.log -E errors.log $ cat hg.pid >> $DAEMON_PIDS revision $ "$TESTDIR/get-with-headers.py" localhost:$HGPORT 'rev/tip' 200 Script output follows <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US"> <head> <link rel="icon" href="/static/hgicon.png" type="image/png" /> <meta name="robots" content="index, nofollow" /> <link rel="stylesheet" href="/static/style-paper.css" type="text/css" /> <script type="text/javascript" src="/static/mercurial.js"></script> <title>test: c78f6c5cbea9</title> </head> <body> <div class="container"> <div class="menu"> <div class="logo"> <a href="http://mercurial.selenic.com/"> <img src="/static/hglogo.png" alt="mercurial" /></a> </div> <ul> <li><a href="/shortlog/c78f6c5cbea9">log</a></li> <li><a href="/graph/c78f6c5cbea9">graph</a></li> <li><a href="/tags">tags</a></li> <li><a href="/bookmarks">bookmarks</a></li> <li><a href="/branches">branches</a></li> </ul> <ul> <li class="active">changeset</li> <li><a href="/raw-rev/c78f6c5cbea9">raw</a></li> <li><a href="/file/c78f6c5cbea9">browse</a></li> </ul> <ul> </ul> <ul> <li><a href="/help">help</a></li> </ul> </div> <div class="main"> <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2> <h3>changeset 1:c78f6c5cbea9 <span class="tag">tip</span> </h3> <form class="search" action="/log"> <p><input name="rev" id="search1" type="text" size="30" /></p> <div id="hint">Find changesets by keywords (author, files, the commit message), revision number or hash, or <a href="/help/revsets">revset expression</a>.</div> </form> <div class="description">del</div> <table id="changesetEntry"> <tr> <th class="author">author</th> <td class="author">test</td> </tr> <tr> <th class="date">date</th> <td class="date age">Thu, 01 Jan 1970 00:00:00 +0000</td></tr> <tr> <th class="author">parents</th> <td class="author"><a href="/rev/cb9a9f314b8b">cb9a9f314b8b</a> </td> </tr> <tr> <th class="author">children</th> <td class="author"></td> </tr> <tr> <th class="files">files</th> <td class="files">a </td> </tr> <tr> <th class="diffstat">diffstat</th> <td class="diffstat"> 1 files changed, 0 insertions(+), 1 deletions(-) <a id="diffstatexpand" href="javascript:toggleDiffstat()"/>[<tt>+</tt>]</a> <div id="diffstatdetails" style="display:none;"> <a href="javascript:toggleDiffstat()"/>[<tt>-</tt>]</a> <p> <table class="stripes2"> <tr> <td class="diffstat-file"><a href="#l1.1">a</a></td> <td class="diffstat-total" align="right">1</td> <td class="diffstat-graph"> <span class="diffstat-add" style="width:0.0%;"> </span> <span class="diffstat-remove" style="width:100.0%;"> </span> </td> </tr> </table> </div> </td> </tr> </table> <div class="overflow"> <div class="sourcefirst linewraptoggle">line wrap: <a class="linewraplink" href="javascript:toggleLinewrap()">on</a></div> <div class="sourcefirst"> line diff</div> <div class="stripes2 diffblocks"> <div class="bottomline inc-lineno"><pre class="sourcelines wrap"> <span id="l1.1" class="minusline">--- a/a Thu Jan 01 00:00:00 1970 +0000</span><a href="#l1.1"></a> <span id="l1.2" class="plusline">+++ /dev/null Thu Jan 01 00:00:00 1970 +0000</span><a href="#l1.2"></a> <span id="l1.3" class="atline">@@ -1,1 +0,0 @@</span><a href="#l1.3"></a> <span id="l1.4" class="minusline">-a</span><a href="#l1.4"></a></pre></div> </div> </div> </div> </div> <script type="text/javascript">process_dates()</script> </body> </html> diff removed file $ "$TESTDIR/get-with-headers.py" localhost:$HGPORT 'diff/tip/a' 200 Script output follows <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US"> <head> <link rel="icon" href="/static/hgicon.png" type="image/png" /> <meta name="robots" content="index, nofollow" /> <link rel="stylesheet" href="/static/style-paper.css" type="text/css" /> <script type="text/javascript" src="/static/mercurial.js"></script> <title>test: a diff</title> </head> <body> <div class="container"> <div class="menu"> <div class="logo"> <a href="http://mercurial.selenic.com/"> <img src="/static/hglogo.png" alt="mercurial" /></a> </div> <ul> <li><a href="/shortlog/c78f6c5cbea9">log</a></li> <li><a href="/graph/c78f6c5cbea9">graph</a></li> <li><a href="/tags">tags</a></li> <li><a href="/bookmarks">bookmarks</a></li> <li><a href="/branches">branches</a></li> </ul> <ul> <li><a href="/rev/c78f6c5cbea9">changeset</a></li> <li><a href="/file/c78f6c5cbea9">browse</a></li> </ul> <ul> <li><a href="/file/c78f6c5cbea9/a">file</a></li> <li><a href="/file/tip/a">latest</a></li> <li class="active">diff</li> <li><a href="/comparison/c78f6c5cbea9/a">comparison</a></li> <li><a href="/annotate/c78f6c5cbea9/a">annotate</a></li> <li><a href="/log/c78f6c5cbea9/a">file log</a></li> <li><a href="/raw-file/c78f6c5cbea9/a">raw</a></li> </ul> <ul> <li><a href="/help">help</a></li> </ul> </div> <div class="main"> <h2 class="breadcrumb"><a href="/">Mercurial</a> </h2> <h3>diff a @ 1:c78f6c5cbea9</h3> <form class="search" action="/log"> <p></p> <p><input name="rev" id="search1" type="text" size="30" /></p> <div id="hint">Find changesets by keywords (author, files, the commit message), revision number or hash, or <a href="/help/revsets">revset expression</a>.</div> </form> <div class="description">del</div> <table id="changesetEntry"> <tr> <th>author</th> <td>test</td> </tr> <tr> <th>date</th> <td class="date age">Thu, 01 Jan 1970 00:00:00 +0000</td> </tr> <tr> <th>parents</th> <td><a href="/file/cb9a9f314b8b/a">cb9a9f314b8b</a> </td> </tr> <tr> <th>children</th> <td></td> </tr> </table> <div class="overflow"> <div class="sourcefirst linewraptoggle">line wrap: <a class="linewraplink" href="javascript:toggleLinewrap()">on</a></div> <div class="sourcefirst"> line diff</div> <div class="stripes2 diffblocks"> <div class="bottomline inc-lineno"><pre class="sourcelines wrap"> <span id="l1.1" class="minusline">--- a/a Thu Jan 01 00:00:00 1970 +0000</span><a href="#l1.1"></a> <span id="l1.2" class="plusline">+++ /dev/null Thu Jan 01 00:00:00 1970 +0000</span><a href="#l1.2"></a> <span id="l1.3" class="atline">@@ -1,1 +0,0 @@</span><a href="#l1.3"></a> <span id="l1.4" class="minusline">-a</span><a href="#l1.4"></a></pre></div> </div> </div> </div> </div> <script type="text/javascript">process_dates()</script> </body> </html> $ cd ..