fix(tests): correct mip4 transition test for subsequent forks

[pdobacz]

Derive pre-transition precompile availability from transitions_from() so MONAD_NINEToMONAD_NEXT passes.

Greptile Summary

This PR fixes the test_fork_transition test so it also passes for subsequent-fork parametrisations (e.g. MONAD_NINEToMONAD_NEXT). The fix introduces a precompile_before flag derived from fork.transitions_from().precompiles() and uses it to set the correct pre-transition expected storage value instead of the previously hard-coded 0.

• Adds precompile_before computation using fork.transitions_from().precompiles() — correct for both the initial MONAD_NINE transition (returns False) and subsequent-fork transitions where the precompile already exists (returns True).
• Updates the expected callee_address storage at slot 14_999 from the hard-coded 0 to 1 if precompile_before else 0, and cleans up a now-stale inline comment at the same line.

Confidence Score: 5/5

Safe to merge — targeted fix to a single test file with no impact on production code.

The precompile_before derivation via fork.transitions_from().precompiles() is consistent with how the framework exposes transition fork metadata, and correctly handles both the initial MONAD_NINE transition and subsequent-fork runs. No logic errors were found.

No files require special attention; the docstring in the single changed file is mildly stale but does not affect correctness.

Important Files Changed

Filename	Overview
tests/monad_nine/mip4_checkreservebalance/test_fork_transition.py	Adds precompile_before flag derived from fork.transitions_from().precompiles() to correctly parameterise the pre-fork expected storage value; logic is correct for both MONAD_NINE and subsequent-fork transitions. Docstring still only describes the MONAD_NINE scenario.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[test_fork_transition runs] --> B{precompile in transitions_from precompiles?}
    B -- Yes - MONAD_NINEToMONAD_NEXT --> C[precompile_before = True]
    B -- No - First transition to MONAD_NINE --> D[precompile_before = False]
    C --> E[Block 14999 - callee slot = 1]
    D --> F[Block 14999 - callee slot = 0]
    E --> G[Block 15000 fork transition - callee slot = 1]
    F --> G
    G --> H[Block 15001 - callee slot = 1]
    H --> I[Assert post state]

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flowchart TD
    A[test_fork_transition runs] --> B{precompile in transitions_from precompiles?}
    B -- Yes - MONAD_NINEToMONAD_NEXT --> C[precompile_before = True]
    B -- No - First transition to MONAD_NINE --> D[precompile_before = False]
    C --> E[Block 14999 - callee slot = 1]
    D --> F[Block 14999 - callee slot = 0]
    E --> G[Block 15000 fork transition - callee slot = 1]
    F --> G
    G --> H[Block 15001 - callee slot = 1]
    H --> I[Assert post state]

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Comments Outside Diff (2)

1. tests/monad_nine/mip4_checkreservebalance/test_fork_transition.py, line 32-37 (link)

   Docstring no longer accurate for subsequent_forks=True

   The docstring still reads "Before the fork, the precompile doesn't exist, so CALL returns empty output". When this test runs for a subsequent transition (e.g. MONAD_NINEToMONAD_NEXT), precompile_before is True and the precompile is already live before the tested fork, so the "before" block gets a 32-byte return, not empty output. The docstring should describe both variants (or at least note the conditional behaviour introduced by subsequent_forks=True).

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: tests/monad_nine/mip4_checkreservebalance/test_fork_transition.py
   Line: 32-37
   
   Comment:
   **Docstring no longer accurate for `subsequent_forks=True`**
   
   The docstring still reads "Before the fork, the precompile doesn't exist, so CALL returns empty output". When this test runs for a subsequent transition (e.g. `MONAD_NINEToMONAD_NEXT`), `precompile_before` is `True` and the precompile is already live before the tested fork, so the "before" block gets a 32-byte return, not empty output. The docstring should describe both variants (or at least note the conditional behaviour introduced by `subsequent_forks=True`).
   
   How can I resolve this? If you propose a fix, please make it concise.

   Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

   

2. tests/monad_nine/mip4_checkreservebalance/test_fork_transition.py, line 110 (link)

   Stale inline comment for the precompile_before=True case

   When precompile_before is True (e.g. MONAD_NINEToMONAD_NEXT), the outer CALL to callee_address still succeeds (result 1), but the precompile is not "returning empty" — it returns 32 bytes. The comment is misleading for the subsequent-fork scenario.

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: tests/monad_nine/mip4_checkreservebalance/test_fork_transition.py
   Line: 110
   
   Comment:
   **Stale inline comment for the `precompile_before=True` case**
   
   When `precompile_before` is `True` (e.g. `MONAD_NINEToMONAD_NEXT`), the outer CALL to `callee_address` still succeeds (result `1`), but the precompile is not "returning empty" — it returns 32 bytes. The comment is misleading for the subsequent-fork scenario.
   
   
   
   How can I resolve this? If you propose a fix, please make it concise.

   Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

   

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