Fixed #24399 -- Made filesystem loaders use more specific exceptions.

[prestontimmons]

No description provided.

[aaugustin]

os.chmod should be before the try. It doesn't make a big difference but that's the common pattern in general.

[prestontimmons]

Thanks. I fixed the docs and updated to a tempfile. That's a much better idea.

[aaugustin]

Rebased and merged in 70123cf. Thanks!

[timgraham]

This test is problematic on Windows:

======================================================================
FAIL: test_notafile_error (template_tests.test_loaders.FileSystemLoaderTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "c:\Users\Tim\code\django\tests\template_tests\test_loaders.py", line 266
, in test_notafile_error
    self.engine.get_template('first')
AssertionError: "Is\ a\ directory" does not match "[Errno 13] Permission denied:
 u'c:\\Users\\Tim\\code\\django\\tests\\template_tests\\templates\\first'"

[prestontimmons]

Okay. I'll take a look into it.

[prestontimmons]

From the testing I did it seems "Permission denied" is the standard message raised on Windows if a directory is passed to open. Since the message can differ per OS, I think the fix is to change assertRaisesMessage(IOError, 'Is a directory') to assertRaises(IOError). I can add a PR if you agree.

[charettes]

Does the raised exception have the same errno on both platforms?

If that's the case you could do:

with self.assertRaises(IOError) as ctx:
    # ....
self.assertEqual(ctx.exception.errno, errno.WHATEVER)

[prestontimmons]

It's different. Linux raises errno.EISDIR (21). Windows raises errno.EACCES (13).

[timgraham]

Seems okay to me. I guess the alternative would to vary the message based on OS. Not sure that complexity is required though.