feat(L1Reader): change to NextUnfinalizedL1MessageQueueIndex and add GetFinalizedStateRootByBatchIndex

[jonastheis]

1. Purpose or design rationale of this PR

change FinalizedL1MessageQueueIndex to NextUnfinalizedL1MessageQueueIndex

2. PR title

Your PR title must follow conventional commits (as we are doing squash merge for each PR), so it must start with one of the following types:

• build: Changes that affect the build system or external dependencies (example scopes: yarn, eslint, typescript)
• ci: Changes to our CI configuration files and scripts (example scopes: vercel, github, cypress)
• docs: Documentation-only changes
• feat: A new feature
• fix: A bug fix
• perf: A code change that improves performance
• refactor: A code change that doesn't fix a bug, or add a feature, or improves performance
• style: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
• test: Adding missing tests or correcting existing tests

3. Deployment tag versioning

Has the version in params/version.go been updated?

• This PR doesn't involve a new deployment, git tag, docker image tag, and it doesn't affect traces
• Yes

4. Breaking change label

Does this PR have the breaking-change label?

• This PR is not a breaking change
• Yes

Summary by CodeRabbit

• New Features
  • Added the ability to fetch finalized state roots by batch index.
• Improvements
  • Updated terminology for message queue index retrieval to improve clarity.

[coderabbitai]

Walkthrough

This update introduces a new method for retrieving finalized state roots by batch index from the ScrollChain contract, adds a constant for the corresponding ABI method name, and renames an existing method to clarify its purpose while simplifying its logic. The new method handles ABI packing, contract calls, and result unpacking with error handling. No other methods or control flows are modified beyond these targeted changes.

Changes

File(s)	Change Summary
rollup/l1/reader.go	Added finalizedStateRoots constant; renamed and simplified FinalizedL1MessageQueueIndex to NextUnfinalizedL1MessageQueueIndex; added new method GetFinalizedStateRootByBatchIndex for contract calls to retrieve finalized state roots by batch index.

Sequence Diagram(s)

sequenceDiagram
    participant Caller
    participant Reader
    participant ScrollChainContract

    Caller->>Reader: GetFinalizedStateRootByBatchIndex(blockNumber, batchIndex)
    Reader->>Reader: Pack calldata for finalizedStateRoots(batchIndex)
    Reader->>ScrollChainContract: Call finalizedStateRoots(batchIndex)
    ScrollChainContract-->>Reader: Return finalized state root (common.Hash)
    Reader->>Caller: Return finalized state root or error

Loading

Possibly related PRs

• feat(L1 follower): add commitAndFinalizeBatch method  #1140: Introduced the finalizedStateRoots ABI method, directly enabling the new contract interaction for finalized state roots by batch index.

Suggested reviewers

• jonastheis
• colinlyguo

Poem

A hop and a jump, a new root to find,
Now batch by batch, the hashes unwind.
With names made clear and logic light,
The chain’s new roots are now in sight.
🐇✨ Onward we go, with code so bright!

---

📜 Recent review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between d178b00 and cdf3f1d.

📒 Files selected for processing (1)

• rollup/l1/reader.go (4 hunks)

🧰 Additional context used

🧬 Code Graph Analysis (1)

rollup/l1/reader.go (1)

interfaces.go (1)

• CallMsg (115-133)

⏰ Context from checks skipped due to timeout of 90000ms (2)

• GitHub Check: test
• GitHub Check: Analyze (go)

🔇 Additional comments (3)

rollup/l1/reader.go (3)

26-26: Looks good - new constant for the ABI method name.

Adding this constant follows the existing pattern in the file for ABI method names, which is good for consistency.

---

76-97: Function rename improves clarity of its purpose.

The function renaming from FinalizedL1MessageQueueIndex to NextUnfinalizedL1MessageQueueIndex better reflects what this method actually returns - the next unfinalized index in the queue. This rename makes the code more self-documenting and improves maintainability.

Also, removing the decrement operation simplifies the logic to align with the function's renamed purpose.

---

121-141:

✅ Verification successful

New method follows established patterns and provides necessary functionality.

This new method GetFinalizedStateRootByBatchIndex follows the same pattern as other contract call methods in the file:

1. Pack the method name and arguments
2. Make the contract call
3. Unpack the result
4. Return the result or appropriate errors

The error handling is thorough and properly contextualized. The implementation is consistent with the codebase's style.

Let's verify that all consumers of this new method are prepared to handle any errors it may return:

---

🏁 Script executed:

#!/bin/bash
# Find where this new method is called to verify error handling
rg -A 3 "GetFinalizedStateRootByBatchIndex" --type go

Length of output: 437

---

No existing consumers for GetFinalizedStateRootByBatchIndex

I searched the codebase for calls to GetFinalizedStateRootByBatchIndex and found none. There are currently no call sites to verify error handling against.

• When you add consumers of this method, ensure each caller properly handles the returned error.

✨ Finishing Touches

• 📝 Generate Docstrings

---

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[yiweichi]

merging this.