On Sun, Aug 30, 2009 at 17:24, Guido van Rossum<gu...@python.org> wrote: > On Sun, Aug 30, 2009 at 4:28 PM, Brett Cannon<br...@python.org> wrote: >> I am going through and running the entire test suite using importlib >> to ferret out incompatibilities. I have found a bunch, although all >> rather minor (raising a different exception typically; not even sure >> they are worth backporting as anyone reliant on the old exceptions >> might get a nasty surprise in the next micro release), and now I am >> down to my last failing test suite: test_import. >> >> Ignoring the execution bit problem (http://bugs.python.org/issue6526 >> but I have no clue why this is happening), I am bumping up against >> TestPycRewriting.test_incorrect_code_name. Turns out that import >> resets co_filename on a code object to __file__ before exec'ing it to >> create a module's namespace in order to ignore the file name passed >> into compile() for the filename argument. Now I can't change >> co_filename from Python as it's a read-only attribute and thus can't >> match this functionality in importlib w/o creating some custom code to >> allow me to specify the co_filename somewhere (marshal.loads() or some >> new function). >> >> My question is how important is this functionality? Do I really need >> to go through and add an argument to marshal.loads or some new >> function just to set co_filename to something that someone explicitly >> set in a .pyc file? Or I can let this go and have this be the one >> place where builtins.__import__ and importlib.__import__ differ and >> just not worry about it? > > ISTR that Bill Janssen once mentioned a file replication mechanism > whereby there were two names for each file: the "canonical" name on a > replicated read-only filesystem, and the longer "writable" name on a > unique master copy. He ended up with the filenames in the .pyc files > being pretty bogus (since not everyone had access to the writable > filesystem). So setting co_filename to match __file__ (i.e. the name > under which the module is being imported) would be a nice service in > this case. > > In general this would happen whenever you pre-compile a bunch of .py > files to .pyc/.pyo and then copy the lot to a different location. Not > a completely unlikely scenario. >
Well, to get this level of compatibility I am going to need to add some magical API somewhere then to overwrite a code object's "file" location. Blah. I will either add an argument to marshal.loads to specify an overriding file path or add an imp.exec that takes a file path argument to override the code object with. > (I was going to comment on the execution bit issue but I realized I'm > not even sure if you're talking about import.c or not. :-) So it turns out a bunch of execution/write bit stuff has come up in Python 2.7 and importlib has been ignoring it. =) Importlib has simply been opening up the bytecode files with 'wb' and writing out the file. But test_import tests that no execution bit get set or that a write bit gets added if the source file lacks it. I guess I can use posix.chmod and posix.stat to copy the source file's read and write bits and always mask out the execution bits. I hate this low-level file permission stuff. -Brett _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
