[issue13959] Re-implement parts of imp in pure Python

[Brett Cannon]

Brett Cannon <brett at python.org> added the comment:

So here is the deal with PyImport_ExecCodeModuleObject(): bootstrapping and Barry has made this a little annoying. =)

First off, PyImport_ImportFrozenModuleObject() uses PyImport_ExecCodeModuleObject(), so that precludes just directly importing imp to handle this function entirely. OK, so that means just trying to chop out the path manipulation stuff since that is duplicating code found in imp/importlib.

The problem, though, is that PyImport_ExecCodeModuleWithPathnames() will take its pathname argument and try to get a source path from it if it points to some .pyc file (PEP 3147 or sourceless .pyc, and if that new path exists then it is used instead of the given path. Unfortunately that API was introduced in Python 3.2, so there is a backwards-compatibility issue in that one can't just rip out the code w/o supporting it. But those semantics are the reason the equivalent of imp.source_from_cache() continues to exist in Python/import.c.

I see two options here. One is to simply leave the C code in, but that has the drawback of duplicated Python and C code. Two is to stick in a call to imp.source_from_cache() between PyImport_ExecCodeModuleWithPathnames() and PyImport_ExecCodeModuleObject() so the former retains the semantics and the latter doesn't pick up the bad habit before 3.3 is released.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue13959>
_______________________________________