main

import "github.com/luxfi/node/internal/regenfixtures"

Command regenfixtures regenerates wire-byte-anchored test fixtures after a wire-format change.

Usage:

go run ./internal/regenfixtures -pkg ./p/block go run ./internal/regenfixtures -pkg ./p/block -dry-run go run ./internal/regenfixtures -pkg ./p/block,./p/state

Algorithm:

1. Run go test -v -count=1 <pkg> and capture stderr+stdout.
2. Parse each failure for expected: []byte{...} and actual: []byte{...} pairs (testify produces both in Not-equal failures).
3. For each (expected, actual) pair, scan the test files in <pkg> using go/parser to find every []byte{...} composite literal. Decode each literal's byte values. If they match expected, rewrite that literal in-place with actual's byte values formatted in canonical 16-bytes-per-line layout.
4. Emit a // Regenerated post-LP-023 ZAP cutover comment above each rewritten literal (idempotent — skip if already present).

Design notes:

• AST-based identification means comments inside the original literal (e.g. // Codec version) are dropped on regenerate. This is correct: the byte boundaries change with the wire format, so the prior comments would lie.

• go/printer is not used to write the new literal because we want deterministic 16-bytes-per-line layout. We render the literal ourselves and string-splice it into the source.

• We disambiguate composite literals by their byte payload, not their position. If the same expected bytes appear in multiple literals in the same file, all are rewritten to the same actual bytes. This is correct iff the test cases are uniquely keyed by their fixture — which is the case for every package we touch (a fixture is one block-or-tx's wire encoding).