fix: prevent intermittent digest-mismatch errors during archive updates

[gruyaume]

Chisel intermittently fails with expected digest X, got Y when Ubuntu's archive is mid-publication and InRelease is temporarily inconsistent with Packages.gz at the named path (a window we observed lasting at least 39 minutes against the same publication in real CI runs for Ella Core). Fetch the package index by content hash using apt's Acquire-By-Hash , which Ubuntu archives have advertised since 16.04 (2016), so the URL itself encodes the expected bytes; falls back to the named path when an archive doesn't advertise the feature or a specific hash has been garbage-collected.

Fixes #295

Reference

• https://wiki.debian.org/DebianRepository/Format#Acquire-By-Hash

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[upils]

Hey @gruyaume, thanks for your PR! Is this ready for review?

[gruyaume]

Hey @gruyaume, thanks for your PR! Is this ready for review?

Yes.

If you find the code changes mostly up to you standards, I am happy to address minor issues. However if there are major issues and you have a completely different idea of the solution, please go ahead and implement it your way. I only want the issue fixed as soon as possible, I don't care about getting the attribution.

[upils]

Yes.

If you find the code changes mostly up to you standards, I am happy to address minor issues. However if there are major issues and you have a completely different idea of the solution, please go ahead and implement it your way. I only want the issue fixed as soon as possible, I don't care about getting the attribution.

Thanks! I explored another approach in parallel but I ended up circling back to yours so there is no point just having another PR for the sake of it. I will review yours then, because I expect only minor changes will be requested.