1644765 - manifest_relpath should be consistent in the use of path separators: \ or /

Status: NEW

(Testing :: Mozbase, defect, P3)

Description

[Rob Wu [:robwu]]

In bug 1644223, tests did not run as expected on Windows because of inconsistent use of path separators with ancestor_manifest.

I fixed this, and touched a line in manifestparser.py that assigns manifest_relpath, which raised a question about the need for path normalization. I looked into it, and found that path separators are not consistently used with manifest_relpath. Often / is expected, but sometimes \ is assigned. This should be fixed (to avoid bugs, and to avoid normalization / post-processing in various places).

I did an exhaustive enumeration of all manifest_relpath occurrences and their use of path separators at:
https://phabricator.services.mozilla.com/D78921#2405289