docs: clarify 20-byte calldata minimum requirement in ERC2771Context

[avorylli]

Add documentation note explaining that forwarded calls require at least 20 bytes of calldata for proper ERC-2771 meta-transaction processing.

Calls with shorter calldata will fall back to returning the forwarder address instead of extracting the original signer.

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[coderabbitai]

Walkthrough

The pull request adds a NOTE to the docblock of the ERC2771Context contract. This NOTE documents that ERC-2771 forwarded calls require calldata of at least 20 bytes. The note explains that if calldata from a trusted forwarder is shorter than this requirement, the _msgSender() function will return the forwarder address instead of extracting the original signer. The documentation also addresses potential fallback behavior and calldata length assumptions. No code logic or public API changes are introduced.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The pull request title "docs: clarify 20-byte calldata minimum requirement in ERC2771Context" directly and accurately describes the main change in the changeset. The raw summary confirms that the PR adds documentation notes to the ERC2771Context.sol contract docblock explaining the 20-byte calldata minimum requirement for ERC-2771 forwarded calls. The title is concise, specific, uses the appropriate "docs:" prefix for documentation changes, and clearly communicates the primary change without vague language. A reviewer scanning the PR history would immediately understand that this is a documentation clarification about calldata requirements in ERC2771Context.
Description Check	✅ Passed	The pull request description is directly related to the changeset and provides meaningful information about the documentation being added. It explains that the PR adds a documentation note about the 20-byte calldata minimum requirement for ERC-2771 meta-transaction processing and describes the fallback behavior when calldata is shorter than the requirement. This matches the raw summary which confirms that the change adds explanatory notes to the ERC2771Context.sol contract docblock. The description is neither off-topic nor excessively vague, and it clearly conveys what documentation content is being added.

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• contracts/metatx/ERC2771Context.sol (1 hunks)

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🔇 Additional comments (1)

contracts/metatx/ERC2771Context.sol (1)

11-15: LGTM! Excellent documentation addition.

This NOTE accurately describes the implementation behavior and provides valuable clarity for developers using ERC2771Context. The documentation correctly explains that:

1. The 20-byte minimum requirement matches _contextSuffixLength() (line 94)
2. The fallback behavior is correctly implemented in _msgSender() (lines 64-69) - when calldataLength < contextSuffixLength, the condition fails and super._msgSender() returns the forwarder's address
3. The note complements (rather than duplicates) the existing WARNING about calldata length dependencies

This helps prevent confusion about edge cases where forwarded calls have minimal or empty calldata.

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[ernestognw]

Thanks