We had previously changed the signature of
`DependencyProvider::get_dependencies` to return an iterator instead of
a hashmap to avoid the conversion cost from our dependencies `Vec` to
the pubgrub's hashmap. These changes are difficult to make in pubgrub
since they complicate the public api. But we don't actually use
`DependencyProvider::get_dependencies`, so we rolled those
customizations back in https://github.com/pubgrub-rs/pubgrub/pull/226
and instead opted to change only the internal
`add_incompatibility_from_dependencies` method that we exposed in our
fork. This aligns us closer with upstream, removes the design questions
about `DependencyProvider` from our concerns and reduces our diff (not
counting the github action) to +36 -12.
This still keeps the resolver state on the stack, but it organizes it
into a more structured representation. This is a precursor to
implementing resolver forking, where we will ultimately put this state
on the heap. The idea is that this will let us maintain multiple
independent resolver states that will all produce their own resolution
(and potentially other forked states).
Closes#3354
Pubgrub got a new feature where all unavailability is a custom, instead
of the reasonless `UnavailableDependencies` and our custom `String` type
previously (https://github.com/pubgrub-rs/pubgrub/pull/208). This PR
introduces a `UnavailableReason` that tracks either an entire version
being unusable, or a specific version. The error messages now also track
this difference properly.
The pubgrub commit is our main rebased onto the merged
https://github.com/pubgrub-rs/pubgrub/pull/208, i'll push
`konsti/main-rebase-generic-reason` to `main` after checking for rebase
problems.
With https://github.com/pubgrub-rs/pubgrub/pull/190, pubgrub attaches
all types to a dependency provider to reduce the number of generics. We
need a dummy dependency provider now to emulate this. On the plus side,
pep440_rs drops its pubgrub dependency.