op-node: Span batch Unprotected Tx Handling + Logic Error Fix

[pcw109550]

Description
This PR fixes two critical errors.

1. Span batch Unprotected Tx

Span batch did not encode/decode correctly for L2 transactions which is not protected(signed with homestead signer), causing L2 unsafe block reorg.
Example input:

0xf86280830f42418252089400000000000000000000000030bd3402deadbeef01801ca048543f9148389fc09f9c37092a255a9550f6748d6fee3d6e066c92f56199f0e1a02003e0128eece7c6ee59d13a9856964c7252034558fe5551b309f033d4d3efb5

Example output(after upper tx encoded and is written to L1, then decoded by derivation):

0xf86480830f42418252089400000000000000000000000030bd3402deadbeef018082072ea048543f9148389fc09f9c37092a255a9550f6748d6fee3d6e066c92f56199f0e1a02003e0128eece7c6ee59d13a9856964c7252034558fe5551b309f033d4d3efb5

This discrepancy was caused because span batch encoding always assumed that legacy transaction will be always protected. THIS IS WRONG. v value was originally 28 but after enc/dec, it becomes 1838 = 901 * 2 + 35 + 1. A disaster!

Therefore, we do have to store bits whether legacy tx is protected or not. All other tx types(access list, eip1559) is always protected. Added protected_bits field. Please refer to the updated specs for the details. This may affect span batch performance, but not much because it adds single bit per L2 legacy transactions.

2. Wrong Inequality

Found out while self reviewing. If window is larger than span, must truncate.

Tests

Ensured than non-protected tx are included at span batch.
Added unit tests for new methods.
Updated unit tests to handle newly added field in span batch txs.

[coderabbitai]

Walkthrough

Walkthrough

The changes across various Go source files and markdown specifications involve the introduction of a new protectedBits field and associated logic for handling protected transactions. The signer variable has been renamed to londonSigner to reflect a specific signing algorithm, and transaction generation logic has been updated to include unprotected transactions. Additionally, tests have been updated to accommodate these changes, and new functions and types have been introduced to support the new transaction protection feature.

Changes

File Path	Change Summary
op-node/rollup/derive/batch_test.go op-node/rollup/derive/span_batch.go op-node/rollup/derive/span_batch_txs.go op-node/rollup/derive/span_batch_txs_test.go	Introduced protectedBits field, updated logic for handling protected transactions, and added new methods and test functions.
op-service/testutils/random.go	Added RandomLegacyTxNotProtected function for generating legacy transactions without explicit signer.
specs/span-batches.md	Reorganized txs field structure to include protected_bits, replaced storage of v with y_parity and protected_bit.
op-node/rollup/derive/span_batch_test.go op-node/rollup/derive/span_batch_tx_test.go	Updated test functions and structs to handle conditional signer assignment.

---

Tips

Chat with CodeRabbit Bot (@coderabbitai)

• If you reply to a review comment from CodeRabbit, the bot will automatically respond.
• To engage with CodeRabbit bot directly around the specific lines of code in the PR, mention @coderabbitai in your review comment
• Note: Review comments are made on code diffs or files, not on the PR overview.
• Add @coderabbitai ignore anywhere in the PR description to prevent this PR from being reviewed.

CodeRabbit Commands (invoked as PR comments)

• @coderabbitai pause to pause the reviews on a PR.
• @coderabbitai resume to resume the paused reviews.
• @coderabbitai review to trigger a review. This is useful when automatic reviews are disabled for the repository.
• @coderabbitai resolve resolve all the CodeRabbit review comments.
• @coderabbitai help to get help.

Note: For conversation with the bot, please use the review comments on code diffs or files.

CodeRabbit Configration File (.coderabbit.yaml)

• You can programmatically configure CodeRabbit by adding a .coderabbit.yaml file to the root of your repository.
• The JSON schema for the configuration file is available here.
• If your editor has YAML language server enabled, you can add the path at the top of this file to enable auto-completion and validation: # yaml-language-server: $schema=https://coderabbit.ai/integrations/coderabbit-overrides.v2.json

[tynes]

Good catch!

[ImTei]

Pushed a commit: improve test cases to cover all tx types including unprotected txs

[trianglesphere]

LGTM. I like the new tests & the shared bit list code.