Support SHA256 hashes in @EXPLICIT files

[jaimergp]

• Ports Add support for SHA256 hashes in explicit files conda/conda#14048
• Relevant CEP at [CEP 23] Text spec input files conda/ceps#79

[Hind-M]

Thanks!

Maybe also add some tests in test_package_info.cpp:

• Always check pkg.md5 and pkg.sha256 values
• Add a section for a hash.size=64 (sha256 case)

Should we support sha256: in urls in this PR as well? (it can be done later otherwise since it's not mandatory).

[jaimergp]

Should we support sha256: in urls in this PR as well? (it can be done later otherwise since it's not mandatory).

I'll try my best 😬

[jjerphan]

Thank you for this contribution, @jaimergp.

This LGTM modulo one discussion.

[jjerphan]

I think we might want to do something in else cases.

How about raising a warning when hashes are malformed?

[jaimergp]

Yes, that sounds sensible. I didn't add them to respect the existing logic (silent ignore). I'm not sure how to add warnings in this codebase, so feel free to commit to the branch directly :)

[jjerphan]

You are right, and thinking again I am not sure we want to add warnings to spam users if this does not cause fatal behavior and if they cannot do anything about it.