Fix memory leak when calloc() fails in php_readline_completion_cb()

Closes GH-18637.

NEWS

@@ -8,6 +8,10 @@ PHP                                                                        NEWS
 - Phar:
   . Add missing filter cleanups on phar failure. (nielsdos)
 
+- Readline:
+  . Fix memory leak when calloc() fails in php_readline_completion_cb().
+    (nielsdos)
+
 05 Jun 2025, PHP 8.3.22
 
 - Core:

ext/readline/readline.c

@@ -458,13 +458,14 @@ char **php_readline_completion_cb(const char *text, int start, int end)
 				/* libedit will read matches[2] */
 				matches = calloc(3, sizeof(char *));
 				if (!matches) {
-					return NULL;
+					goto out;
 				}
 				matches[0] = strdup("");
 			}
 		}
 	}
 
+out:
 	zval_ptr_dtor(&params[0]);
 	zval_ptr_dtor(&_readline_array);