zend_get_callable_name: Return underlying callable’s name for fake closures

NEWS

@@ -169,6 +169,8 @@ PHP                                                                        NEWS
 - Standard:
   . Fixed crypt() tests on musl when using --with-external-libcrypt
     (Michael Orlitzky).
+  . Fixed bug GH-18062 (is_callable(func(...), callable_name: $name) for first
+    class callables returns wrong name). (timwolla)
 
 - Streams:
   . Fixed bug GH-16889 (stream_select() timeout useless for pipes on Windows).

UPGRADING.INTERNALS

@@ -19,6 +19,8 @@ PHP 8.5 INTERNALS UPGRADE NOTES
     a value to a non-reference zval.
   . Added zval_ptr_safe_dtor() to safely destroy a zval when a destructor
     could interfere.
+  . zend_get_callable_name() now returns the name of the underlying function
+    for fake closures.
 
 ========================
 2. Build system changes

Zend/tests/first_class_callable/gh18062.phpt

@@ -0,0 +1,32 @@
+--TEST--
+First Class Callable returns correct name from is_callable()
+--FILE--
+<?php
+
+class Foo {
+	public function __invoke() {
+
+	}
+
+	public static function bar() { 
+
+	}
+}
+
+function some_func() {
+
+}
+
+is_callable(some_func(...), callable_name: $name);
+var_dump($name);
+
+is_callable((new Foo())(...), callable_name: $name);
+var_dump($name);
+
+is_callable(Foo::bar(...), callable_name: $name);
+var_dump($name);
+?>
+--EXPECT--
+string(9) "some_func"
+string(13) "Foo::__invoke"
+string(8) "Foo::bar"

Zend/zend_API.c

@@ -4134,6 +4134,19 @@ ZEND_API zend_string *zend_get_callable_name_ex(zval *callable, zend_object *obj
 		case IS_OBJECT:
 		{
 			zend_class_entry *ce = Z_OBJCE_P(callable);
+
+			if (ce == zend_ce_closure) {
+				const zend_function *fn = zend_get_closure_method_def(Z_OBJ_P(callable));
+
+				if (fn->common.fn_flags & ZEND_ACC_FAKE_CLOSURE) {
+					if (fn->common.scope) {
+						return zend_create_member_string(fn->common.scope->name, fn->common.function_name);
+					} else {
+						return zend_string_copy(fn->common.function_name);
+					}
+				}
+			}
+
 			return zend_string_concat2(
 				ZSTR_VAL(ce->name), ZSTR_LEN(ce->name),
 				"::__invoke", sizeof("::__invoke") - 1);