AutoMerge: switch to RegistryInstances

[ericphanson]

this ends up kind of undoing #614 because it seemed easier to use RegistryInstances everywhere. Now we can use packed registries everywhere except the RegistryCI.jl-based check which needs to support older Julia's. In particular, this should make it more feasible to set up a "local" version that users can use without needing a unpacked registry.

written by claude-code but with a very annoying amount of iteration, probably it would have been faster to do it myself.

The most gnarly checks here are the deps and julia compat, and I tested that we got the same results on the latest release of all 11k packages (this did reveal a bug in the initial implementation, in which there was only a julia dep and no other deps). I also included some tests with the old version on a few packages to show they are the same, but we could delete those tests before merging if we want.

[codecov]

Codecov Report

❌ Patch coverage is 66.94915% with 39 lines in your changes missing coverage. Please review.
✅ Project coverage is 51.20%. Comparing base (9818af3) to head (3b03c9b).

Files with missing lines	Patch %	Lines
AutoMerge/src/guidelines.jl	69.76%	13 Missing ⚠️
AutoMerge/src/dependency_confusion.jl	0.00%	8 Missing ⚠️
AutoMerge/src/package_path_in_registry.jl	0.00%	6 Missing ⚠️
AutoMerge/src/registry_helpers.jl	84.84%	5 Missing ⚠️
AutoMerge/src/jll.jl	0.00%	4 Missing ⚠️
AutoMerge/src/semver.jl	78.57%	3 Missing ⚠️

❌ Your project check has failed because the head coverage (51.20%) is below the target coverage (70.00%). You can increase the head coverage or adjust the target coverage.

❗ There is a different number of reports uploaded between BASE (9818af3) and HEAD (3b03c9b). Click for more details.

HEAD has 13 uploads less than BASE

Flag	BASE (9818af3)	HEAD (3b03c9b)
	24	11

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #643       +/-   ##
===========================================
- Coverage   78.40%   51.20%   -27.21%     
===========================================
  Files          29       29               
  Lines        1936     1914       -22     
===========================================
- Hits         1518      980      -538     
- Misses        418      934      +516     

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[DilumAluthge]

So, if I understand correctly, you're only using RegistryInstances (and the packed registry) for the upstream registry head, right? For the checked-out PR branch, you're still using the unpacked registry that we have checked out on disk?

Do I have that correct?

[ericphanson]

no, I'm using RegistryInstances for both. It can handle both packed and unpacked registries

[ericphanson]

@GunnarFarneback I know you might not have time for a full review, but do you have any thoughts on this approach?

[GunnarFarneback]

I think it's generally fine and simplifies some of the registry analysis code.