Map<String, Object> parentMap = new LinkedHashMap<>();
        DocMap docMap = new DocMap(parentMap);

        docMap.put("c_key", "value_c");
        docMap.put("a_key", "value_a");
        docMap.put("lang", "en");
        docMap.put("b_key", "value_b");

        Set<Map.Entry<String, Object>> entrySet = docMap.entrySet();
        String[] keys = entrySet.stream().map(Map.Entry::getKey).toArray(String[]::new);

        indexUpdateCallback.mergeResponseData(dataMap, responseDataMap);

        assertEquals(1, dataMap.size());
        assertEquals("X1", dataMap.get("x"));
    }

    /** Case 3: Only overwrite key (baseKey not set) → generate baseKey, remove overwrite key */
    @Test
    public void test_mergeResponseData_overwriteOnly() {
        Map<String, Object> dataMap = new HashMap<>();
        Map<String, Object> responseDataMap = new HashMap<>();

        byte[] labelBytes = label.getBytes(java.nio.charset.StandardCharsets.UTF_8);
        byte[] input = new byte[baseKey.length + labelBytes.length + (context != null ? context.length : 0)];

        int pos = 0;
        System.arraycopy(baseKey, 0, input, pos, baseKey.length);
        pos += baseKey.length;
        System.arraycopy(labelBytes, 0, input, pos, labelBytes.length);
        pos += labelBytes.length;

			return c, err
		}

		arnKey := p.roleArn
		if p.RolePolicy == "" {
			arnKey = DummyRoleARN
			// Ensure that at most one JWT policy claim based provider may be
			// defined.
			if _, ok := c.arnProviderCfgsMap[DummyRoleARN]; ok {
				return c, errSingleProvider
			}
		}

		c.arnProviderCfgsMap[arnKey] = &p
		c.ProviderCfgs[cfgName] = &p

		return 0, nil
	}
	o.debugln("searching for ", search)
	var tmp metacacheBlock
	json := jsoniter.ConfigCompatibleWithStandardLibrary
	i := 0
	for {
		partKey := fmt.Sprintf("%s-metacache-part-%d", ReservedMetadataPrefixLower, i)
		v, ok := fi.Metadata[partKey]
		if !ok {
			o.debugln("no match in metadata, waiting")
			return -1, io.ErrUnexpectedEOF
		}
		err := json.Unmarshal([]byte(v), &tmp)
		if !ok {

			info.ETag = getDecryptedETag(headers, *info, false)
		}
	}

	return encrypted, nil
}

type (
	objectMetaEncryptFn func(baseKey string, data []byte) []byte
	objectMetaDecryptFn func(baseKey string, data []byte) ([]byte, error)
)

// metadataEncrypter returns a function that will read data from input,
// encrypt it using the provided key and return the result.

	ArrayWildcard  bool       `parser:"| @\"[*]\""`         // [*] form
}

// JSONPath represents a keypath.
// Instances should be treated idempotent and not change once created.
type JSONPath struct {
	BaseKey  *Identifier        `parser:" @@"`
	PathExpr []*JSONPathElement `parser:"(@@)*"`

	// Cached values:
	pathString         string
	strippedTableAlias string
	strippedPathExpr   []*JSONPathElement
}

	// Transfer SSEC key in opts.EncryptFn
	if crypto.SSEC.IsRequested(r.Header) {
		key, err := ParseSSECustomerRequest(r)
		if err == nil {
			// Set EncryptFn to return SSEC key
			opts.EncryptFn = func(baseKey string, data []byte) []byte {
				return key
			}
		}
	}
	if _, ok := r.Header[xhttp.MinIOSourceReplicationRequest]; ok {
		opts.ReplicationRequest = true