Reproducibility of staticfiles manifests

[Linus Heckemann]

Paths in staticfiles manifests appear in a nondeterministic order in the resulting JSON file. I assume this would often reflect the order in which files are listed by the operating system, given dict's insertion order preservation, but there are probably many more factors affecting this.

This can sometimes (but may not always -- this depends heavily on filesystem behaviour) be reproduced by running collectstatic in projects using ManifestStaticFilesStorage across different copies of the project source.

Sorting them would result in more comparable results, smaller diffs and (depending on the environment) more efficient deployments.

[Sarah Boyce]

Hi Linus, would you be able to create a test project with some instructions as to how to reproduce this behavior?
If this is an issue we will need to be able to confirm it's fixed

[Andreas Pelme]

It may be hard to show this exact problem since it depends on the OS/file systems used. The problem is the list of paths in the staticfiles manifest.

Somewhat related, see ​https://github.com/django/django/pull/16411/files#diff-f5c7100e3528e9f6edb98cd5a3d33133bdde6286a89fa472f89980fb07364a8eR486. It sorts the paths before hashing them. If it would not sort the keys, the hash could change. I tried changing sorted() to list() on that line and ran the test suite and there were no test failures. So testing this is a bit tricky to test properly!