Fixed res leak

Author: laruence

Zend/zend_exceptions.c

@@ -587,13 +587,14 @@ ZEND_METHOD(exception, getTraceAsString)
 
 	DEFAULT_0_PARAMS;
 
-	res = estrdup("");
-	str = &res;
-
 	trace = zend_read_property(default_exception_ce, getThis(), "trace", sizeof("trace")-1, 1 TSRMLS_CC);
 	if(Z_TYPE_P(trace) != IS_ARRAY) {
 		RETURN_FALSE;
 	}
+
+	res = estrdup("");
+	str = &res;
+
 	zend_hash_apply_with_arguments(Z_ARRVAL_P(trace) TSRMLS_CC, (apply_func_args_t)_build_trace_string, 3, str, len, &num);
 
 	s_tmp = emalloc(1 + MAX_LENGTH_OF_LONG + 7 + 1);