[Xtley001]

Summary

Resolves #853. When provider.header(&parent_hash) returns None due to Reth secondary index lag, falls back to provider.header_by_number(block - 1) and verifies hash_slow() == parent_hash before entering the polling sleep loop.

Problem

In Reth, canonical commits write to the primary Headers table before updating the secondary HeaderNumbers (BlockHash -> BlockNumber) index. During slot transitions, provider.header(&parent_hash) can return None for hundreds of milliseconds. try_to_read_block_header queried provider.header_by_number but discarded the header and returned an error, forcing wait_for_block_header into repeated polling sleeps and delaying block building.

Solution

• When provider.header(&parent_hash)? yields None, inspect provider.header_by_number(block - 1).
• If header.hash_slow() == parent_hash, return Ok(header) immediately.
• If the hash mismatches or the header is absent, preserve the existing diagnostic logging and return the error.
• Protect against block 0 underflow via block.checked_sub(1).
• Added regression tests covering:
  1. Primary hash lookup hit
  2. Number lookup fallback hit on hash miss
  3. Hash mismatch (fork / reorg safety)
  4. Block 0 underflow protection

Testing

• Automated regression tests added in crates/rbuilder/src/live_builder/mod.rs

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota. Try requesting a review at a lower effort level.

An organization owner can choose the repository organization as the billing source for reviews requested by members with a paid Copilot license. Learn about Copilot code review billing. Review the Copilot code review billing settings.