[issue21313] Py_GetVersion() is broken when using mqueue and a long patch name

[Eric Snow]

New submission from Eric Snow:

Py_GetVersion() (in Python/getversion.c) builds the version string returned by sys.version:

  PyOS_snprintf(version, sizeof(version), "%.80s (%.80s) %.80s",
            PY_VERSION, Py_GetBuildInfo(), Py_GetCompiler());

In turn, Py_GetBuildInfo() (in Modules/getbuildinfo.c) returns the "build" portion of Python's version string.  When available, the tag returned by "hg id -t" constitutes part of that build string.

The problem is that when using mqueue the result of "hg id -t" can be pretty long.  For example:

  issue21226-fix-PyImport_ExecCodeModuleObject.diff qbase qtip tip

That's 74 characters for just part of a build string that may be well over 100 characters.  However, Py_GetVersion() truncates it to 80 characters.

The consequence is that this value of sys.version causes platform._sys_version() to fail since the version string does not match the expected pattern.

So either Py_GetVersion() should relax (-1) or Py_GetBuildInfo() should restrict the length of the resulting build string (+1).  Would it work to truncate just the hgid part so that the whole string returned by Py_GetBuildInfo() is no more than length 80?  E.g.


-    PyOS_snprintf(buildinfo, sizeof(buildinfo),
-                  "%s%s%s, %.20s, %.9s", hgid, sep, revision, DATE, TIME);
+    PyOS_snprintf(buildinfo, 80,
+                  "%.43s%.1s%.13s, %.20s, %.9s", hgid, sep, revision, DATE, TIME);

----------
components: Interpreter Core
messages: 216883
nosy: eric.snow
priority: normal
severity: normal
stage: patch review
status: open
title: Py_GetVersion() is broken when using mqueue and a long patch name
type: behavior
versions: Python 2.7, Python 3.4, Python 3.5

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<http://bugs.python.org/issue21313>
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