From f3fdf570b3cd3df14af3d698950d341623a97088 Mon Sep 17 00:00:00 2001 From: Nikita Popov Date: Mon, 12 Aug 2019 16:58:52 +0200 Subject: Intern alias old_name early This is likely going to end up interned lateron at some point when the new_name is referenced somewhere. However, it may be that there are some uses that do not get interned before that. In this case we will intern a string that already have zval users, without updating the refcounted flag on those zvals. In particular this can happen with something like [Foo::class], where Foo is an imported symbol. The string it resolves to won't get interned right away, but may be interned later. use Foo as Bar; $x = [Bar::class]; var_dump(Bar::X); debug_zval_dump($x); // Will show negative refcount class Foo { const X = 1; } However, this doesn't really fix the root cause, there are probably other situations where something similar can occur. --- Zend/zend_compile.c | 1 + 1 file changed, 1 insertion(+) diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c index a91dfeeecf..f25ce2f55d 100644 --- a/Zend/zend_compile.c +++ b/Zend/zend_compile.c @@ -6619,6 +6619,7 @@ void zend_compile_use(zend_ast *ast) /* {{{ */ } zend_string_addref(old_name); + old_name = zend_new_interned_string(old_name); if (!zend_hash_add_ptr(current_import, lookup_name, old_name)) { zend_error_noreturn(E_COMPILE_ERROR, "Cannot use%s %s as %s because the name " "is already in use", zend_get_use_type_str(type), ZSTR_VAL(old_name), ZSTR_VAL(new_name)); -- cgit v1.2.1