Bug report: image_volume.py time_stamp breaks reproducible builds

[bmwiedemann]

Environment

OS: all (openSUSE-Tumbleweed-20230728)
Python version: all

Description

While working on reproducible builds for openSUSE, I found that
building our python-pyface package twice resulted in such diffs:

--- old//usr/lib/python3.11/site-packages/pyface/image/library/icons.zip/image_volume.py        2023-07-30 13:29:14.000000000 +0200
+++ new//usr/lib/python3.11/site-packages/pyface/image/library/icons.zip/image_volume.py        2039-09-01 02:45:16.000000000 +0200
@@ -4,7 +4,7 @@
     category='General',
     keywords=[],
     aliases=[],
-    time_stamp='20230730132924',
+    time_stamp='20390901024527',
     info=[

There should be a way to get deterministic build results, e.g. allow to override the build timestamp with SOURCE_DATE_EPOCH.

Steps to Reproduce

do a clean build twice

[corranwebster]

Thanks for the report, although I don't think this is an issue with Pyface. I'm not sure why your build is touching the icons.zip file. You should be able to treat that as a fixed asset from the point of view of linux packaging.

[bmwiedemann]

It seems, icons.zip is modified by the unittests:
https://code.opensuse.org/package/python-pyface/blob/3ea62406bddb3d455d2d0cc4be6661d24d7b95ea/f/python-pyface.spec#_88
maybe in pyface/image/tests/test_image.py ?

[corranwebster]

Yes, I think there are tests which test the correct regeneration of the zip archives. Tests shouldn't be run on as part of actually creating a build artefact though? I'd think you'd want to run the tests on the result of the reproducible build.

[bmwiedemann]

This seems to be an effect of how we build with rpmbuild. There tests run before bundling up files. Will try to avoid it there.

[bmwiedemann]

We solved it now via https://build.opensuse.org/request/show/1131679 by copying PYTHONPATH / python_sitelib before a test.