Look up remote imports dynamically when doing frozen check

[elliotdavies]

Description of the change

To fix #349 we no longer look for packages.dhall directly when checking that the remote imports are frozen. Instead we look at spago.dhall and check all remote imports in its dependency graph.

Checklist:

• Added the change to the "Unreleased" section of the changelog
• Added some example of the new feature to the README
• Added a test for the contribution (if applicable)

P.S.: the above checks are not compulsory to get a change merged, so you may skip them. However, taking care of them will result in less work for the maintainers and will be much appreciated 😊

[elliotdavies]

@f-f Submitting this as a draft to check I'm working along the same lines as you were thinking. If so I'll do the tests, changelog, etc.

The _stack part of the Status didn't seem to contain much, but I was able to retrieve what we need from _graph instead.

[f-f]

@elliotdavies yes this is exactly what I was looking for! I left some minor suggestions but it's almost ready to go 🙂

[elliotdavies]

@f-f Ace - I'll try to get this done today in the hopes of making the v10 release 😄

[elliotdavies]

@f-f Ready to re-review I think!

[f-f]

Looks great, thanks a lot @elliotdavies! 👏

[elliotdavies]

@f-f Awesome! One other thing - at the moment we call freeze once per local import, so in a large monorepo setup you might see Generating new hashes... quite a few times. It's not a huge issue but the UX is a bit odd. Is it overkill to add a shouldEcho flag to freeze, or something?

[f-f]

@elliotdavies great point, and I'm not sure how to solve it. We could try moving the print around (e.g. in ensureFrozen instead of freeze), but let's take that in another PR so we can see the changes separately from this, which I'll merge now. Thank you! 🙂