collectstatic overwrites newer files in remote storage

[Paolo Dente]

The change to django/contrib/staticfiles/management/commands/collectstatic.py in commit 2cd2d188516475ddf256e6267cd82c495fb5c430 causes the command to overwrite all static files in remote storage (eg. S3), instead of only updatable ones.

A quick workaround is to override the command and restore the previous Command.delete_file() in the subclass, but I suppose this should be fixed.

[Tim Graham]

Could you be more specific about the steps to reproduce the issue (ideally without S3 involved since Django's test suite cannot rely on that)? If you could provide a test case for tests/staticfiles_tests that would be great.

[Rebkavets Vitali]

This line ​Github link
full_path for remote storages such as S3 is always None
The clause was improperly refactored
It should look like

...
                    if (target_last_modified.replace(microsecond=0) >= source_last_modified.replace(microsecond=0) and
                            if not full_path or full_path and not (self.symlink ^ os.path.islink(full_path))):
...

[Paolo Dente]

@Tim: as far as I can tell, any non-local storage should be affected so a possible test would require mocking Storage or the management command so that Command.local() is False; I can try and write one. On the other hand, it looks like @Vitali spotted the problem with the refactoring, so I don't know how to proceed from here.

[Claude Paroz]

The next step is to write a test that demonstrates the current regression.

[Rebkavets Vitali]

​PR

[Rebkavets Vitali]

Here is a code snippet demonstrating the problem with the refactoring:

​http://ideone.com/3kkY7N

[Tim Graham]

I added a test to the PR.

[Tim Graham <timograham@…>]

In c85831e4:

Fixed #27658 -- Prevented collectstatic from overwriting newer files in remote storages.

Thanks revimi for the initial patch.

[Tim Graham <timograham@…>]

In da9b36c5:

[1.10.x] Fixed #27658 -- Prevented collectstatic from overwriting newer files in remote storages.

Thanks revimi for the initial patch.

Backport of c85831e4b7b5a7e4249df10327175b7251cb012d from master