offset trie improvments

[goodlyrottenapple]

offset trie fixes/improvements:

• constructor validates the data forms a tree, i.e. each child has
  exactly one parent and no nodes are unreachable
• Bound path length at MAX_PATH_NIBBLES as the decoder assumes the
  encoding is always a short string
• Rework checked_end onto offsets, fixing an out-of-bounds read
• hashes_ insert is now guarded on the RLP length, enforcing the
  invariant that only hash-referenced nodes get cached in the map

[Copilot]

Pull request overview

This PR cleans up RLP encoding paths in the offset-format witness trie by making “hash-as-RLP” handling explicit and reusable, reducing ad-hoc memcpy/encode patterns and improving type-safety around fixed-size hash RLP payloads.

Changes:

• Define HASH_RLP_LEN in terms of KECCAK256_SIZE and introduce hash_rlp_view for fixed-size RLP-encoded hashes.
• Add DigestView::hash_rlp() and update account leaf code-hash accessors to return a dedicated hash RLP view.
• Centralize hash RLP encoding/copying via OffsetTrie::encode_rlp(...) overloads and use them at call sites.

Verdict: CORRECT

Generated with Claude Code

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
category/execution/ethereum/db/offset_trie.hpp	Introduces hash_rlp_view, adds digest/hash RLP view helpers, and centralizes hash RLP emission via encode_rlp overloads.
category/execution/ethereum/db/offset_trie.cpp	Switches account-leaf encoding to use the new encode_rlp(l.code_hash_rlp(), ...) helper instead of manual memcpy.

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[github-actions]

Clean, semantically-equivalent refactor: hash_rlp_view encodes the fixed 33-byte RLP-hash extent in the type, DigestView::hash_rlp() leans on the DIGEST == 0x80 + KECCAK256_SIZE invariant (guarded by the existing static_assert), and the two new OffsetTrie::encode_rlp overloads collapse three ad-hoc memcpy/shrink sites into one call. One P3 nit inline about an adjacent open-coded storage_root write in AccountLeafView encoding that the same helper could take over.

Verdict: CORRECT

🤖 Generated with Claude Code