zend_builtin_functions: Add clone() as function

Zend/tests/clone/clone_005.phpt

@@ -0,0 +1,43 @@
+--TEST--
+Clone as a function.
+--FILE--
+<?php
+
+$x = new stdClass();
+
+\var_dump(\clone($x));
+\var_dump(\array_map('clone', [$x, $x, $x]));
+
+class Foo {
+    private function __clone() {
+
+    }
+
+    public function clone_me() {
+        // Verify visibility when going through array_map().
+        return array_map(\clone(...), [$this]);
+    }
+}
+
+$f = new Foo();
+
+$clone = $f->clone_me()[0];
+
+var_dump($f !== $clone);
+
+?>
+--EXPECTF--
+object(stdClass)#%d (0) {
+}
+array(3) {
+  [0]=>
+  object(stdClass)#%d (0) {
+  }
+  [1]=>
+  object(stdClass)#%d (0) {
+  }
+  [2]=>
+  object(stdClass)#%d (0) {
+  }
+}
+bool(true)

Zend/zend_API.c

@@ -3641,6 +3641,7 @@ static void zend_disable_function(const char *function_name, size_t function_nam
 	if (UNEXPECTED(
 		(function_name_length == strlen("exit") && !memcmp(function_name, "exit", strlen("exit")))
 		|| (function_name_length == strlen("die") && !memcmp(function_name, "die", strlen("die")))
+		|| (function_name_length == strlen("clone") && !memcmp(function_name, "clone", strlen("clone")))
 	)) {
 		zend_error(E_WARNING, "Cannot disable function %s()", function_name);
 		return;

Zend/zend_builtin_functions.c

@@ -69,6 +69,52 @@ zend_result zend_startup_builtin_functions(void) /* {{{ */
 }
 /* }}} */
 
+ZEND_FUNCTION(clone)
+{
+	zend_object *zobj;
+
+	ZEND_PARSE_PARAMETERS_START(1, 1)
+		Z_PARAM_OBJ(zobj)
+	ZEND_PARSE_PARAMETERS_END();
+
+	zend_class_entry *scope = zend_get_executed_scope();
+
+	zend_class_entry *ce = zobj->ce;
+	zend_function *clone = ce->clone;
+
+	if (UNEXPECTED(zobj->handlers->clone_obj == NULL)) {
+		zend_throw_error(NULL, "Trying to clone an uncloneable object of class %s", ZSTR_VAL(ce->name));
+		RETURN_THROWS();
+	}
+
+	if (clone && !(clone->common.fn_flags & ZEND_ACC_PUBLIC)) {
+		if (clone->common.scope != scope) {
+			if (UNEXPECTED(clone->common.fn_flags & ZEND_ACC_PRIVATE)
+			 || UNEXPECTED(!zend_check_protected(zend_get_function_root_class(clone), scope))) {
+				zend_throw_error(NULL, "Call to %s %s::__clone() from %s%s",
+					zend_visibility_string(clone->common.fn_flags), ZSTR_VAL(clone->common.scope->name),
+					scope ? "scope " : "global scope",
+					scope ? ZSTR_VAL(scope->name) : ""
+				);
+				RETURN_THROWS();
+			}
+		}
+	}
+
+	zend_object *cloned;
+	cloned = zobj->handlers->clone_obj(zobj);
+
+	if (EG(exception)) {
+		if (cloned) {
+			OBJ_RELEASE(cloned);
+		}
+
+		RETURN_THROWS();
+	}
+
+	RETURN_OBJ(cloned);
+}
+
 ZEND_FUNCTION(exit)
 {
 	zend_string *str = NULL;

Zend/zend_builtin_functions.stub.php

@@ -7,6 +7,8 @@ class stdClass
 {
 }
 
+function _clone(object $object): object {}
+
 function exit(string|int $status = 0): never {}
 
 /** @alias exit */

build/gen_stub.php

@@ -1009,6 +1009,9 @@ class FunctionName implements FunctionOrMethodName {
     private /* readonly */ Name $name;
 
     public function __construct(Name $name) {
+        if ($name->name === '_clone') {
+            $name = new Name('clone', $name->getAttributes());
+        }
         $this->name = $name;
     }