phar: Fix memory leak when setAlias() fails

Closes phpGH-20135.

Author: ndossche

NEWS

@@ -17,6 +17,7 @@ PHP                                                                        NEWS
 
 - Phar:
   . Fix memory leak of argument in webPhar. (nielsdos)
+  . Fix memory leak when setAlias() fails. (nielsdos)
 
 - Random:
   . Fix Randomizer::__serialize() w.r.t. INDIRECTs. (nielsdos)

ext/phar/phar_object.c

@@ -2770,6 +2770,7 @@ PHP_METHOD(Phar, setAlias)
 	phar_flush(phar_obj->archive, NULL, 0, 0, &error);
 
 	if (error) {
+		pefree(phar_obj->archive->alias, phar_obj->archive->is_persistent);
 		phar_obj->archive->alias = oldalias;
 		phar_obj->archive->alias_len = oldalias_len;
 		phar_obj->archive->is_temporary_alias = old_temp;