test(stm): recover the ignored IVC prover input preparation tests

[hjeljeli32]

Content

The seven #[ignore] prepare_* tests in proof_system::ivc_halo2_snark::prover_input never ran. Two were broken rather than dormant: prepare no longer dispatches to prepare_genesis and prove now rejects a genesis rolling state, so both built a context the production code refuses and failed with invalid epoch transition at last committed epoch 0. The other five cost about 8 s each, all of it setup: each built a full IvcSnarkProverSetup, deserializing a 1.0 GB recursive proving key and a 96 MB SRS that prepare never reads.

prepare reads only the certificate verifying key, the KZG verifier parameters and the two fixed-base maps, all of which are already committed as test assets. In CI the 7ests cost 1.9 s in total (0.018-0.391 s each), against an estimated 80-92 s per slow run had they been promoted on the full setup; prove_all_scenarios is unchanged at 1409 s.

Changes

• Narrowed verification seam (prover_setup.rs, prover_input.rs, prover_input_helpers.rs, proof.rs): a new IvcProverInputVerificationContext with private fields and two constructors — the production one derives the verifier parameters from the setup's own SRS rather than the embedded production constant, the test one derives both fixed-base maps from the supplied keys. prepare, verify_certificate_proof and build_next_accumulator take it; the proving key stays in the setup, first read by prove_with_transcript.
• Two obsolete tests retired (prover_input.rs): the base-case happy path needs a Poseidon-transcript proof of the genesis step that no committed asset carries, and prove_all_scenarios' bootstrap path already runs that scenario with a real prover; the genesis-signature case belongs to prepare_genesis, where it is already covered. Both of its surviving assertions moved onto the positive genesis test.
• Asset-built fixtures (prover_input.rs): the three OnceLock cells amortized nothing under nextest's process-per-test model and are replaced by one helper building Global and the context from the same decoded keys. Asset-sourced key material stays checked rather than trusted: both positive tests verify the committed previous Poseidon proof against that Global.
• Fast tier (prover_input.rs, .github/workflows/scripts/filter-slow-tests.sh): the seven tests leave mod slow, which is deleted, and the now-unmatched self-module entry is dropped. The cross-module proof:: entry stays, so a PR touching this file still runs prove_all_scenarios; .config/nextest.toml is unchanged, and the test module is renamed test to tests.

Pre-submit checklist

• Branch
  • Tests are provided (if possible)
  • Crates versions are updated (if relevant)
  • CHANGELOG file is updated (if relevant)
  • Commit sequence broadly makes sense
  • Key commits have useful messages
• PR
  • All check jobs of the CI have succeeded
  • Self-reviewed the diff
  • Useful pull request description
  • Reviewer requested
• Documentation
  • No new TODOs introduced

Issue(s)

Closes #3466

[github-actions]

Test Results

     5 files  ± 0     221 suites  ±0   2h 3m 12s ⏱️ + 59m 51s
 3 515 tests +65   3 515 ✅ +65  0 💤 ±0  0 ❌ ±0 
11 529 runs  +74  11 529 ✅ +74  0 💤 ±0  0 ❌ ±0 

Results for commit 65a4c66. ± Comparison against base commit 66d8896.

♻️ This comment has been updated with latest results.

[Copilot]

Pull request overview

This PR narrows the dependency surface of IvcProverInput::prepare by introducing a verification-only context type, enabling previously #[ignore]d prover-input preparation tests to run fast in CI by sourcing only verifier-side assets (no proving key / SRS heavy setup).

Changes:

• Introduces IvcProverInputVerificationContext and routes prepare/certificate verification/accumulator folding through it instead of the full IvcSnarkProverSetup.
• Refactors prover_input.rs tests to remove the slow OnceLock fixtures and rely on committed verification-context assets, promoting the tests out of the slow/ignored tier.
• Updates slow-test filtering to reflect the removal of the prover_input slow module entry.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
mithril-stm/src/proof_system/ivc_halo2_snark/prover_setup.rs	Adds IvcProverInputVerificationContext and a setup method to construct it from verifier-side artifacts.
mithril-stm/src/proof_system/ivc_halo2_snark/prover_input.rs	Updates prepare to take the new context and rewrites tests to use embedded assets (fast CI).
mithril-stm/src/proof_system/ivc_halo2_snark/prover_input_helpers.rs	Switches helper functions from full setup dependency to verification context dependency.
mithril-stm/src/proof_system/ivc_halo2_snark/proof.rs	Adjusts prover flow to pass verification context into prepare.
mithril-stm/src/circuits/halo2_ivc/bench/helpers.rs	Updates bench helper paths to use verification context for off-circuit checks/folding.
.github/workflows/scripts/filter-slow-tests.sh	Removes the now-unmatched slow-test filter entry for prover_input module.

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[jpraynaud]

LGTM 👍

[damrobi]

LGTM 👍