take into list of crates for easyconfigs using Cargo-based easyblock when determining checksums for patches

[boegel]

for for failing CI:

ERROR: test__parse_easyconfig_DeltaLake-0.15.1-gfbf-2023a.eb (test.easyconfigs.easyconfigs.EasyConfigTest)
Test for easyconfig DeltaLake-0.15.1-gfbf-2023a.eb
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.6.15/x64/lib/python3.6/site-packages/easybuild/tools/filetools.py", line 1274, in verify_checksum
    checksum = checksum[filename]
KeyError: 'DeltaLake-0.15.1_remove-obsolete-pyarrow-hotfix.patch'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/runner/work/easybuild-easyconfigs/easybuild-easyconfigs/test/easyconfigs/easyconfigs.py", line 1693, in innertest
    template_easyconfig_test(self, spec_path)
  File "/home/runner/work/easybuild-easyconfigs/easybuild-easyconfigs/test/easyconfigs/easyconfigs.py", line 1533, in template_easyconfig_test
    if not verify_checksum(patch_full, checksum):
  File "/opt/hostedtoolcache/Python/3.6.15/x64/lib/python3.6/site-packages/easybuild/tools/filetools.py", line 1276, in verify_checksum
    raise EasyBuildError("Missing checksum for %s in %s", filename, checksum)
easybuild.tools.build_log.EasyBuildError: "Missing checksum for DeltaLake-0.15.1_remove-obsolete-pyarrow-hotfix.patch in {'addr2line-0.21.0.tar.gz': '8a30b2e23b9e17a9f90641c7ab1549cd9b44f296d3ccbf309d2863cfe398a0cb'}"

This problem arose due to the change in easybuilders/easybuild-easyblocks#3448, where self.cfg = self.cfg.copy() was added to the Cargo constructor before self.cfg['sources'] is being changed...

The checksum for DeltaLake-0.15.1_remove-obsolete-pyarrow-hotfix.patch is already there in DeltaLake-0.15.1-gfbf-2023a.eb

[Flamefire]

Can't we use the actual list of sources as will be done by the checksums step?
I.e. app.cfg['sources'] as discussed in the other PR/issue

[boegel]

Not since the change in easybuilders/easybuild-easyblocks#3448, because ec['sources'] no longer contains also the crates since that change, that's exactly why this fix is required

[Flamefire]

Since that change app.cfg['sources'] should be populated with the crates while ec['sources'] should not. Or did I miss anything? See the comment

x = app_class(EasyConfig(file_content))
x.cfg <-- always do this

[Flamefire]

I created an alternative PR: #21419

Taking the sources, patches and checksums from app.cfg there and in a single place.

[Flamefire]

where self.cfg = self.cfg.copy() was added to the Cargo constructor before self.cfg['sources'] is being changed...

Just for clarification: Actual issue is not the change of of self.cfg but the implicit change of the passed in ec instance we use here for the test. See the comment.