Function Set

parser.go:1018–1147

* Set - Receives existing data structure, path to set, and data to set at that key. Returns: `value` - modified byte array `err` - On any parsing error */ SYS-REQ-009, SYS-REQ-051, SYS-REQ-068, SYS-REQ-069, SYS-REQ-070, SYS-REQ-110

(data []byte, setValue []byte, keys ...string)

*/
// SYS-REQ-009, SYS-REQ-051, SYS-REQ-068, SYS-REQ-069, SYS-REQ-070, SYS-REQ-110
func Set(data []byte, setValue []byte, keys ...string) (value []byte, err error) {
	// ensure keys are set
	if len(keys) == 0 {
		return nil, KeyPathNotFoundError
	}

	_, _, startOffset, endOffset, err := internalGet(data, keys...)
	if err != nil {
		if err != KeyPathNotFoundError {
			// problem parsing the data
			return nil, err
		}
		// full path doesnt exist
		// does any subpath exist?
		var depth int
		for i := range keys {
			_, _, start, end, sErr := internalGet(data, keys[:i+1]...)
			if sErr != nil {
				break
			} else {
				endOffset = end
				startOffset = start
				depth++
			}
		}
		comma := true
		object := false
		// KI-3: when the path's next component expects one container type but
		// the existing structure is the other (array-index [N] under an object,
		// or an object key under an array), auto-coerce the container to the
		// type expected by the path and proceed with fresh insertion. The
		// mismatched container is treated as if it needs to be (re)created, so
		// the output is always valid JSON.
		coerceTopLevel := false
		coerceStart := 0
		if endOffset == -1 {
			firstToken := nextToken(data)
			if firstToken < 0 {
				return nil, KeyPathNotFoundError
			}
			pathIsIndex := len(keys[0]) > 0 && keys[0][0] == '['
			// An empty trailing key component is the degenerate "no path
			// provided" case (SYS-REQ-111), not a real object key — it must
			// keep returning KeyPathNotFoundError on a non-object root, so it
			// is excluded from auto-coerce.
			pathIsObjectKey := len(keys[0]) > 0 && !pathIsIndex
			dataIsObject := data[firstToken] == '{'
			dataIsArray := data[firstToken] == '['
			if (pathIsIndex && dataIsObject) || (pathIsObjectKey && dataIsArray) {
				// SYS-REQ-009: cross-type Set at the top level — replace the
				// mismatched container with a fresh container of the type the
				// path expects, then perform a fresh insertion.
				coerceTopLevel = true
				coerceStart = firstToken
				comma = false
				object = !pathIsIndex
				endOffset = lastToken(data)
			} else if !dataIsObject {