Ignore sepolia-devnet-2 L1 in superchain chainspec generation

[LukaszRozmej]

Changes

• Add sepolia-devnet-2 to IGNORED_L1S in scripts/superchain.py, alongside the already-ignored sepolia-dev-0 devnet.

The superchain registry added a sepolia-devnet-2/sepolia-devnet-2 devnet whose L1 is not in the script's constants table (L1ChainId, L1BeaconGenesisSlotTime, DepositContractAddress). The generated chainspec then enables EIP-6110 (Isthmus) without depositContractAddress, which fails chainspec validation and broke all Nethermind.Runner.Test smoke tests in #12395.

After this change, the "Update OP Superchain chains" workflow needs a re-run to regenerate #12395 without the devnet files.

Types of changes

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a change that causes existing functionality not to work as expected)
• Optimization
• Refactoring
• Documentation update
• Build-related changes

Testing

Requires testing

• Yes
• No

Notes on testing

Ran scripts/superchain.py locally: the devnet is now skipped (Ignoring 'sepolia-devnet-2-sepolia-devnet-2') and the remaining 49 chain configs generate unchanged.

Documentation

Requires documentation update

• Yes
• No

Requires explanation in Release Notes

• Yes
• No

🤖 Generated with Claude Code

[claude]

Claude finished @LukaszRozmej's task in 48s —— View job

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Code Review: Ignore sepolia-devnet-2 L1 in superchain chainspec generation

• Read changed file (scripts/superchain.py) and diff vs origin/master
• Verify correctness of the fix against the filtering logic
• Check for edge cases / regressions
• Post review

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Verdict: ✅ Looks good — safe to merge

The one-line change is correct and matches the existing pattern.

Why it works: In main(), each chain's identifier is split into l1/chainName and filtered with if chainName in IGNORED_CHAINS or l1 in IGNORED_L1S (scripts/superchain.py:355-357). Since the new devnet's identifier is sepolia-devnet-2/sepolia-devnet-2, its l1 is sepolia-devnet-2, so adding it to IGNORED_L1S skips it as intended.

Root-cause confirmed: The constants table in to_nethermind_chainspec only defines mainnet/sepolia keys (superchain.py:78-91). For an unknown L1, lookup(constants, ["DepositContractAddress", l1]) returns None, which filter_none then drops from params — while eip6110TransitionTimestamp is still set from isthmus_time (line 227). EIP-6110 enabled without a depositContractAddress is exactly what fails chainspec validation, consistent with the #12395 smoke-test breakage.

The change is minimal, focused, and consistent with the already-ignored sepolia-dev-0.

Findings

Low (non-blocking, optional) — The constants table is an implicit allow-list, but the manual IGNORED_L1S denylist is the enforcement mechanism. Any future superchain-registry devnet on a new L1 will silently regenerate an invalid chainspec and re-break the smoke tests until someone manually adds it here. A more robust design would fail-fast or auto-skip when l1 is absent from constants (e.g. warn + continue when L1ChainId/DepositContractAddress lookups are None), so the failure is self-explanatory rather than surfacing downstream as a validation error. This is a design suggestion for a follow-up, not something that should block this fix.

No Critical / High / Medium issues found.
· branch fix/superchain-ignore-sepolia-devnet-2