When deleting files on WIN32, open files cannot be removed.
This is especially a problem for compiled Python modules which
remain open once imported.
Previously it was not as common for add-ons to include compiled Python
modules however with extensions supporting Python-wheels,
it's increasingly likely users run into this.
Workaround the problem by:
- Scheduling the files for removal next time Blender starts.
- Rename paths that cannot be removed to avoid collisions when
the paths is reused (re-installing for example).
This is supported for:
- Extensions.
- Python wheels.
- Legacy user add-ons.
- App-templates.
Details:
- On startup, a file exists that indicates cleanup is needed.
In the common case the file doesn't exist.
Otherwise module paths are scanned for files to remove.
- Since errors resolving paths to remove could result in user data loss,
ensure the paths are always within the (extension/addon/app-template)
directory.
- File locking isn't used, if multiple Blender instances start at the
same time and try to remove the same files, this won't cause errors.
Even so, remove the checking file immediately avoid unnecessary
file-system access overhead for other Blender instances.
Also resolves#125049.
fc6a99e0d2