Function runValidConsistencyGate

encoding_json_fuzz_test.go:174–208

============================================================================= Gate A: NO-PANIC (embedded in every gate via encodingJSONNoPanic) ============================================================================= Gate A is not a standalone function: every json.* call throughout the gates b

(t *testing.T, data []byte)

// These two code paths share the same scanner internally but have
// historically diverged on edge cases (trailing data, malformed escapes).
func runValidConsistencyGate(t *testing.T, data []byte) {
	t.Helper()
	valid := json.Valid(data)

	var v interface{}
	var unmarshalErr error
	encodingJSONNoPanic(t, "ValidConsistency/Unmarshal", data, func() {
		unmarshalErr = json.Unmarshal(data, &v)
	})

	if valid && unmarshalErr != nil {
		// json.Unmarshal into interface{} represents numbers as float64,
		// which cannot hold values like 1e999 (would be +Inf). This is a
		// DOCUMENTED design choice of encoding/json (the docs say "float64,
		// for JSON numbers"), NOT a syntactic Valid/Unmarshal divergence —
		// it is the same number-range limitation the spec says to document
		// rather than flag. Re-verify with json.Number (which has no
		// float64-range constraint): if the number-aware decode succeeds,
		// this is the float64-range case; only flag if json.Number ALSO
		// fails, which would indicate a genuine syntactic inconsistency.
		dec := json.NewDecoder(bytes.NewReader(data))
		dec.UseNumber()
		var nv interface{}
		if dErr := dec.Decode(&nv); dErr == nil {
			return // float64-range limitation — documented non-bug.
		}
		t.Errorf("Gate B: json.Valid==true but Unmarshal failed even under "+
			"UseNumber (genuine consistency bug): err=%v data=%s",
			unmarshalErr, truncateForMsg(data))
	}
	if !valid && unmarshalErr == nil {
		t.Errorf("Gate B: json.Valid==false but Unmarshal succeeded (consistency bug): "+
			"data=%s", truncateForMsg(data))
	}
}

// =============================================================================
// Gate C: Unmarshal → Marshal → Unmarshal round-trip equivalence