pythoncuri...@gmail.com writes: > Hi,
Hi, I have a guess at explaining the behaviour you describe - see below. > I'm having problem when I'm trying to import modules using the > imp.load_module function. > At the end of this post there's some code I wrote to illustrate the > problem. > The code istself doesn't make much sense, but what I'm trying to do in > reality is allow people to customize an application by writing a small > python module. If I find a file in a known location with a known name, > I'll import it and use some data or function in it. > I ran into problems when writing unit tests for it. > > What happens when run my code is this: > > .E > ====================================================================== > ERROR: test_2 (__main__.Test) > ---------------------------------------------------------------------- > Traceback (most recent call last): > File "test_import.py", line 30, in test_2 > getattr(imported, 'y') > AttributeError: 'module' object has no attribute 'y' > ---------------------------------------------------------------------- > Ran 2 tests in 0.015s > > > So it seems that test_2 fails. It does pretty much the same thing as > test_1, but with different data. > Changing test_2 to check for 'x' instead of 'y' makes it pass, but > that's not the result I should get. > So it seems that I still have the module that I imported in test_1. > > So, I'm thinking that I might be dealing with some sort of gc issue. > I add the "time.sleep(1)", (commented in the code) and the tests pass. > 'y' is found in test_2. > Replacing the sleep with a gc.collect() makes the test fail again, so > garbage collection doesn't seem to help. > > I've tried it on python 2.6.1 on windows, 2.5.2 in cygwin and 2.6.1 on > solaris with the same results. > Could anyone explain what I am missing? > > Thanks > /Mattias > > Here's the code: > > import unittest > import tempfile, os, imp, time, gc > > module_file_name=os.path.join(tempfile.gettempdir(), 'my_module.py') > > def write_module(data): > f = open(module_file_name, 'w') > f.write(data) > f.close() > > def import_from_file(path): > imported_module = imp.load_source(module_file_name, path) > return imported_module > > class Test(unittest.TestCase): > def tearDown(self): > os.unlink(module_file_name) > > def test_1(self): > module_data='''x=1''' > write_module(module_data) > imported=import_from_file(module_file_name) This will compile the module and create a 'my_module.pyc' file. > getattr(imported, 'x') > > def test_2(self): > # time.sleep(1) > module_data='''y=2''' > write_module(module_data) > imported=import_from_file(module_file_name) My guess is that without the sleep(1), the imp.load_source function will use the compiled file 'my_module.pyc' created in test_1 instead of compiling the new 'my_module.py' file. This would be because the new 'my_module.py' file is created so soon after the last compilation of the module that they have the same timestamp, thus fooling imp.load_source into thinking that 'my_module.py' was not modified since its last compilation. > getattr(imported, 'y') > > if __name__ == "__main__": > unittest.main() HTH -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
