Rocq --config Fix

[Durbatuluk1701]

Reflecting on the issue in #13774, I think a solution that is both forwards and backwards compatible is to just always use rocq c --config. This PR implements this change and allows compilation of rocq.theory stanzas for Rocq 9.0+.

Documentation in the Rocq CLI implies this will be recognized by compile/c and the message for this commit seems to imply that --config will need to access the environment regardless.

Maybe there is some reason to utilize just rocq --config (note: missing the c), but it is not immediately obvious to me.

It working with PR dune vs. failing previous version

$ rocq --version
The Rocq Prover, version 9.0.1
compiled with OCaml 5.3.0

$ cat theories/dune
(rocq.theory
 (name test_proj)
 (package test_proj)
 (theories Stdlib))

$ cat dune-project
(lang dune 3.22)
(using rocq 0.12)
(generate_opam_files)
(package
 (name test_proj)
 (depends rocq-core))

$ cat theories/Test.v
From Stdlib Require Import Nat.

Lemma test : forall (x : nat), x = x.
Proof.  reflexivity. Qed.

$ ~/forks/dune/_boot/dune.exe build

$ ~/forks/dune/_boot/dune.exe clean

$ dune build
Warning: Skipping installed theories due to 'rocq --config' failure:
- .../.opam/package_dev/bin/rocq --config failed with exit code 1.
Hint: Try running 'rocq --config' manually to see the error.
Couldn't find Rocq standard library, and theory is not using (stdlib no)
-> required by _build/default/theories/.test_proj.theory.d
-> required by alias theories/all
-> required by alias default
File "theories/dune", line 4, characters 11-17:
4 |  (theories Stdlib))
               ^^^^^^
Theory "Stdlib" has not been found.
-> required by theory test_proj in theories/dune:2
-> required by _build/default/theories/.test_proj.theory.d
-> required by alias theories/all
-> required by alias default

[rlepigre-skylabs-ai]

I think this is a reasonable approach, although I would consider it inferior to falling back to rocq c --config if rocq --config fails (not sure how hard that would be to do). The current approach would make it harder for Rocq to remove the --config option from rocq c, which I think would make sense eventually (CLI flags are kind of a mess in Rocq). That being said, I'm fine if we want to simply merge this.

[rlepigre-skylabs-ai]

We probably don't want this, right @Alizter?

[Alizter]

Actually, I think its fine. Otherwise the runtest-rocq alias will not build. We don't use test-all in CI anyway.

[Alizter]

@Durbatuluk1701 could you ask the Rocq maintainers on Zulip if they intend to change this flag in the future. That would probably give us the clearest path forward.

[Durbatuluk1701]

@Durbatuluk1701 could you ask the Rocq maintainers on Zulip if they intend to change this flag in the future. That would probably give us the clearest path forward.

Asked here

[Durbatuluk1701]

The endorsed fix is:

Always check rocq c --config: it works with 9.0, and if is not planned to get deprecated may be forward and backwards compatible

Which I think should align with what this PR currently contributes

[Alizter]

Could you add a changelog entry?