custom snapshots in 2.3.1 ingore git location if hackage package exists

[rpeszek]

General summary/comments (optional)

Using custom snapshot.yaml resolver does not appear to be working properly if git locations are specified for a newer version
of a hackage project.
(I have tested this with a checked-in cabal files as well, so this does not seem to be related to #5210 ).

This appears to be a regression
See #3714

Things work fine if specified project was never uploaded to hackage.

Steps to reproduce

I have create a test project to demonstrate this.

1. clone https://github.com/juris-futura/test-stack-snapshot
2. run stack build (will fail suggesting to add typed-encoding-0.4.2.0 to stack.yaml even though the snapshot has git hash
   with package.yaml pointing to 0.4.9.0
3. STACK_YAML=stack-works.yaml stack build will work just fine - this replays the same configuration directly in stack-works.yaml
4. reverting to stack v1.9.3 will also work.

Alternatively

1. Fork a project that has been uploaded to hackage.
2. Create a branch with newer version in package.yaml and push it to github
3. Use that project as your dependency. Specify this dep in some custom snapshot (resolver=mysnapshot.yaml) and specify your git commit hash in that snapshot.

Similar steps have been listed in old #3714
see DanBurton commented on Jan 5, 2018 with unordered containers.

Expected

Dependency will be picked up from the custom snapshot

Actual

Stack ignores snapshot dependency and suggest adding the wrong dependency found in hackage.

Example output

$ stack build
Cloning 9078a21d2d0ac745aa48a8d065e1dc4c0369ff45 from git@github.com:rpeszek/dag-check
Cloning e938fcb63f5f18bf1dda5e5aad0ac0be660b18d1 from git@github.com:rpeszek/typed-encoding
DEPRECATED: The package at Repo from git@github.com:rpeszek/typed-encoding, commit e938fcb63f5f18bf1dda5e5aad0ac0be660b18d1 does not include a cabal file.
Instead, it includes an hpack package.yaml file for generating a cabal file.
This usage is deprecated; please see https://github.com/commercialhaskell/stack/issues/5210.
Support for this workflow will be removed in the future.

Error: While constructing the build plan, the following exceptions were encountered:

In the dependencies for test-stack-snapshot-0.1.0.0:
    typed-encoding needed, but the stack configuration has no specified version  (latest matching version is 0.4.2.0)
needed since test-stack-snapshot is a build target.

Some different approaches to resolving this:

  * Recommended action: try adding the following to your extra-deps in /.../test-stack-snapshot/stack.yaml:

- typed-encoding-0.4.2.0@sha256:8b92de5f695ccf295990365e9f46bd2d904ec15e1c9c3e0578e4eb56b1ee27ff,5217

Plan construction failed.

Stack version

$ stack --version
Version 2.3.1, Git revision de2a7b694f07de7e6cf17f8c92338c16286b2878 (8103 commits) x86_64 hpack-0.33.0

Method of installation

• curl -sSL https://get.haskellstack.org/ | sh
  (with possibly stack upgrade)