ci: Fix --index-state for hackage roundtrip tests

[mpickering]

As a principle, tests which are required for CI to pass should be
reproducible and not depending on external resources changes or being
modified. The hackage tests currently violate this by depending on the
latest index state from hackage. This is problematic because until the
test is fixed all merges into master are blocked. Even though the
patches in question have nothing to do with the test.

It would be more suitable for a nightly job to run on the latest index
and for normal CI to run with a fixed index which is updated
periodically in a controlled manner.

Fixes #10284

[ulysses4ever]

I fully support the idea. But I'm also worried about the proliferation of pinned index states in this repo. It'd almost be better to use grep in validate.sh to extract the index state from one of the project files instead.

[jasagredo]

Looks good. Perhaps we could skip the merge delay for this one as it is blocking every other PR.

And probably it would be worth creating an issue pointing to where the error in the parsing comes from now that you already investigated that a bit.

[fgaz]

Merging now to unbreak CI

[geekosaur]

@mergify backport 3.12

[mergify]

backport 3.12

✅ Backports have been created

• #10305 ci: Fix --index-state for hackage roundtrip tests (backport #10285) has been created for branch 3.12

[geekosaur]

Could someone who's analyzed this please create an issue as mentioned above? I'm trying to look into why this is failing, and all I've got so far is a missing test-suite and that the PackageDescription has been (possibly deliberately) ellipsized; and TBHJ I don't have a whole lot of an idea what I'm looking at, aside from the obvious that it's failing to parse io-classes-1.6.0.0's cabal file.

[mpickering]

@geekosaur I think you need #10287 and the related issue #10283

[geekosaur]

Ah, so it's already fixed, but the PR is pending on 2 open discussions and a merge conflict (validate.sh is a stub for `cabal-validate; the corresponding change, which I made for my own local test, is at https://github.com/haskell/cabal/blob/master/cabal-validate/src/Main.hs#L276-L285). (Linking this comment in the other PR.)