**Root-cause and responsibility analysis (required):**
1. Treat the reported location as the starting point, then verify the problem, direct cause, and root cause in the current code.
2. Classify it as an independent local issue or a structural issue involving responsibility, source of truth, or contract.
3. For a structural issue, identify the authoritative requirement, specification, schema, or public contract, and search as needed for implementations with the same meaning, contract, and root cause. Do not treat the finding's counterexamples as the upper bound, and exclude responsibilities that are merely visually similar.
4. Identify the valid conditions, forbidden conditions, and boundary values that apply, then map them to participating entries, types and schemas, validation boundaries, consumers, state, side effects, and failure paths that actually exist. For dimensions that the source of truth or implementation defines as finite sets, such as enums, locales, optional presence, state transitions, input formats, or candidate ordering, make every applicable member and state concrete. For an ordered candidate set with a result limit, distinguish a qualifying member inside the retained range, at the first excluded or any later position, and no match when those states actually exist. Follow delegated helpers beyond their call names: record the delegating caller-to-helper relationship that imposes the constraint, whether that delegation causes the current failure, and the actual result limit, search order, no-match behavior, and fallback, then trace every applicable highest-level real entry through the helper to the consumer and terminal. Do not enumerate unrelated state dimensions.
5. Treat unresolved issues and unmigrated contract paths confirmed to share the same cause as one fix unit.
6. Check evidence that could disprove the assumed cause, and revise the analysis before editing when it does.