* which returns more comprehensive result in case of an error, and has
* more parsing options.
*
+ * In PHP versions before 7.1, decoding a JSON string containing an empty key
+ * without passing $assoc as true results in a return object with a property
+ * named "_empty_" (because true empty properties were not supported pre-PHP-7.1).
+ * Instead, consider passing $assoc as true to return an associative array.
+ *
+ * But be aware that in all supported PHP versions, decoding an empty JSON object
+ * with $assoc = true returns an array, not an object, breaking round-trip consistency.
+ *
+ * See https://phabricator.wikimedia.org/T206411 for more details on these quirks.
+ *
* @param string $value The JSON string being decoded
* @param bool $assoc When true, returned objects will be converted into associative arrays.
*