Function setPathSemanticallyValid

reference_oracle_test.go:409–446

setPathSemanticallyValid reports whether applying Set/Delete with `path` to a doc marshaled from `v` is well-defined: each array-index component must address an array element of an existing array (in-range), each object-key component must address an object field. Out-of-range indices on nested array

(v interface{}, path []string)

// known bugs (D6, D7, D8 in the file header) — callers should NOT assert
// strict round-trip correctness on those paths.
func setPathSemanticallyValid(v interface{}, path []string) bool {
	cur := v
	for i, comp := range path {
		isArrayIdx := len(comp) > 0 && comp[0] == '['
		switch node := cur.(type) {
		case map[string]interface{}:
			if isArrayIdx {
				return false // D6: array-index syntax on object — undefined
			}
			if existing, ok := node[comp]; ok {
				cur = existing
			} else {
				// New key only well-defined if it's the LAST component
				// (Set creates one new key; multi-component paths through
				// a new key are undefined).
				return i == len(path)-1
			}
		case []interface{}:
			if !isArrayIdx {
				return false // object-key syntax on array — undefined
			}
			idxStr := strings.TrimSuffix(strings.TrimPrefix(comp, "["), "]")
			idx, err := strconv.Atoi(idxStr)
			if err != nil || idx < 0 {
				return false
			}
			if idx >= len(node) {
				// D7: out-of-range index on nested array — known data-loss bug.
				return false
			}
			cur = node[idx]
		default:
			// Trying to descend into a scalar — undefined.
			return false
		}
	}
	return true
}

// ---------------------------------------------------------------------------
// Property 1: Get round-trip — jsonparser.Get matches encoding/json.