[RFC] Extend #[\Override] to target properties (#19061)

RFC: https://wiki.php.net/rfc/override_properties

Co-authored-by: Tim Düsterhus <tim@bastelstu.be>

NEWS

@@ -12,6 +12,7 @@ PHP                                                                        NEWS
   . The backtick operator as an alias for shell_exec() has been deprecated.
     (timwolla)
   . Returning null from __debugInfo() has been deprecated. (DanielEScherzer)
+  . Support #[\Override] on properties. (Jiří Pudil)
 
 - Curl:
   . The curl_close() function has been deprecated. (DanielEScherzer)

UPGRADING

@@ -178,6 +178,8 @@ PHP 8.5 UPGRADE NOTES
     RFC: https://wiki.php.net/rfc/pipe-operator-v3
   . Constructor property promotion can now be used for final properties.
     RFC: https://wiki.php.net/rfc/final_promotion
+  . #[\Override] can now be applied to properties.
+    RFC: https://wiki.php.net/rfc/override_properties
 
 - Curl:
   . Added support for share handles that are persisted across multiple PHP

Zend/tests/attributes/override/properties_01.phpt

@@ -0,0 +1,39 @@
+--TEST--
+#[\Override]: Properties
+--FILE--
+<?php
+
+interface I {
+    public mixed $i { get; }
+}
+
+interface II extends I {
+    #[\Override]
+    public mixed $i { get; }
+}
+
+class P {
+    public mixed $p1;
+    public mixed $p2;
+}
+
+class PP extends P {
+    #[\Override]
+    public mixed $p1;
+    public mixed $p2;
+}
+
+class C extends PP implements I {
+    #[\Override]
+    public mixed $i;
+    #[\Override]
+    public mixed $p1;
+    public mixed $p2;
+    public mixed $c;
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_02.phpt

@@ -0,0 +1,15 @@
+--TEST--
+#[\Override]: Properties: No parent class.
+--FILE--
+<?php
+
+class C {
+    #[\Override]
+    public mixed $c;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: C::$c has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_03.phpt

@@ -0,0 +1,21 @@
+--TEST--
+#[\Override]: Properties: No parent class, but child implements matching interface.
+--FILE--
+<?php
+
+interface I {
+    public mixed $i { get; }
+}
+
+class P {
+    #[\Override]
+    public mixed $i;
+}
+
+class C extends P implements I {}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: P::$i has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_04.phpt

@@ -0,0 +1,21 @@
+--TEST--
+#[\Override]: Properties: No parent class, but child implements matching interface (2).
+--FILE--
+<?php
+
+interface I {
+    public mixed $i { get; }
+}
+
+class C extends P implements I {}
+
+class P {
+    #[\Override]
+    public mixed $i;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: P::$i has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_05.phpt

@@ -0,0 +1,26 @@
+--TEST--
+#[\Override]: Properties: No parent interface.
+--FILE--
+<?php
+
+interface I {
+    #[\Override]
+    public mixed $i { get; }
+}
+
+interface II extends I {}
+
+
+class C implements II {
+    public mixed $i;
+}
+
+class C2 implements I {
+    public mixed $i;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: I::$i has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_06.phpt

@@ -0,0 +1,15 @@
+--TEST--
+#[\Override]: Properties: On trait.
+--FILE--
+<?php
+
+trait T {
+    #[\Override]
+    public mixed $t;
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_07.phpt

@@ -0,0 +1,19 @@
+--TEST--
+#[\Override]: Properties: On used trait without parent property.
+--FILE--
+<?php
+
+trait T {
+    #[\Override]
+    public mixed $t;
+}
+
+class Foo {
+    use T;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: Foo::$t has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_08.phpt

@@ -0,0 +1,23 @@
+--TEST--
+#[\Override]: Properties: On used trait with interface property.
+--FILE--
+<?php
+
+trait T {
+    #[\Override]
+    public mixed $i;
+}
+
+interface I {
+    public mixed $i { get; }
+}
+
+class Foo implements I {
+    use T;
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_09.phpt

@@ -0,0 +1,19 @@
+--TEST--
+#[\Override]: Properties: Parent property is private, child property is public.
+--FILE--
+<?php
+
+class P {
+    private mixed $p;
+}
+
+class C extends P {
+    #[\Override]
+    public mixed $p;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: C::$p has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_10.phpt

@@ -0,0 +1,19 @@
+--TEST--
+#[\Override]: Properties: Parent property is private, child property is private.
+--FILE--
+<?php
+
+class P {
+    private mixed $p;
+}
+
+class C extends P {
+    #[\Override]
+    private mixed $p;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: C::$p has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_11.phpt

@@ -0,0 +1,19 @@
+--TEST--
+#[\Override]: Properties: Parent property is protected, child property is public.
+--FILE--
+<?php
+
+class P {
+    protected mixed $p;
+}
+
+class C extends P {
+    #[\Override]
+    public mixed $p;
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_12.phpt

@@ -0,0 +1,19 @@
+--TEST--
+#[\Override]: Properties: Parent property is protected, child property is protected.
+--FILE--
+<?php
+
+class P {
+    protected mixed $p;
+}
+
+class C extends P {
+    #[\Override]
+    protected mixed $p;
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_13.phpt

@@ -0,0 +1,21 @@
+--TEST--
+#[\Override]: Properties: Redeclared trait property.
+--FILE--
+<?php
+
+trait T {
+    public mixed $t;
+}
+
+class C {
+    use T;
+
+    #[\Override]
+    public mixed $t;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: C::$t has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_14.phpt

@@ -0,0 +1,25 @@
+--TEST--
+#[\Override]: Properties: Redeclared trait property with interface.
+--FILE--
+<?php
+
+interface I {
+    public mixed $i { get; }
+}
+
+trait T {
+    public mixed $i;
+}
+
+class C implements I {
+    use T;
+
+    #[\Override]
+    public mixed $i;
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_15.phpt

@@ -0,0 +1,19 @@
+--TEST--
+#[\Override]: Properties: Valid anonymous class.
+--FILE--
+<?php
+
+interface I {
+    public mixed $i { get; }
+}
+
+new class () implements I {
+    #[\Override]
+    public mixed $i;
+};
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_16.phpt

@@ -0,0 +1,21 @@
+--TEST--
+#[\Override]: Properties: Invalid anonymous class.
+--FILE--
+<?php
+
+interface I {
+    public mixed $i { get; }
+}
+
+new class () implements I {
+    public mixed $i;
+
+    #[\Override]
+    public mixed $c;
+};
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: I@anonymous::$c has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_17.phpt

@@ -0,0 +1,16 @@
+--TEST--
+#[\Override]: Properties: Static property no parent class.
+--FILE--
+<?php
+
+class C
+{
+    #[\Override]
+    public static mixed $c;
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: C::$c has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/tests/attributes/override/properties_18.phpt

@@ -0,0 +1,19 @@
+--TEST--
+#[\Override]: Properties: Static property.
+--FILE--
+<?php
+
+class P {
+    public static mixed $p;
+}
+
+class C extends P {
+    #[\Override]
+    public static mixed $p;
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_19.phpt

@@ -0,0 +1,21 @@
+--TEST--
+#[\Override]: Properties: valid promoted property
+--FILE--
+<?php
+
+interface I {
+    public mixed $i { get; }
+}
+
+class C implements I {
+    public function __construct(
+        #[\Override]
+        public mixed $i,
+    ) {}
+}
+
+echo "Done";
+
+?>
+--EXPECT--
+Done

Zend/tests/attributes/override/properties_20.phpt

@@ -0,0 +1,17 @@
+--TEST--
+#[\Override]: Properties: invalid promoted property
+--FILE--
+<?php
+
+class C {
+    public function __construct(
+        #[\Override]
+        public mixed $c,
+    ) {}
+}
+
+echo "Done";
+
+?>
+--EXPECTF--
+Fatal error: C::$c has #[\Override] attribute, but no matching parent property exists in %s on line %d

Zend/zend_attributes.stub.php

@@ -68,7 +68,7 @@ final class SensitiveParameterValue
 /**
  * @strict-properties
  */
-#[Attribute(Attribute::TARGET_METHOD)]
+#[Attribute(Attribute::TARGET_METHOD|Attribute::TARGET_PROPERTY)]
 final class Override
 {
     public function __construct() {}

Zend/zend_attributes_arginfo.h

@@ -1,5 +1,5 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: 9aee3d8f2ced376f5929048444eaa2529ff90311 */
+ * Stub hash: 715016d1ff1b0a6abb325a71083eff397a080c44 */
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_Attribute___construct, 0, 0, 0)
 	ZEND_ARG_TYPE_INFO_WITH_DEFAULT_VALUE(0, flags, IS_LONG, 0, "Attribute::TARGET_ALL")
@@ -230,7 +230,7 @@ static zend_class_entry *register_class_Override(void)
 	zend_string *attribute_name_Attribute_class_Override_0 = zend_string_init_interned("Attribute", sizeof("Attribute") - 1, 1);
 	zend_attribute *attribute_Attribute_class_Override_0 = zend_add_class_attribute(class_entry, attribute_name_Attribute_class_Override_0, 1);
 	zend_string_release(attribute_name_Attribute_class_Override_0);
-	ZVAL_LONG(&attribute_Attribute_class_Override_0->args[0].value, ZEND_ATTRIBUTE_TARGET_METHOD);
+	ZVAL_LONG(&attribute_Attribute_class_Override_0->args[0].value, ZEND_ATTRIBUTE_TARGET_METHOD | ZEND_ATTRIBUTE_TARGET_PROPERTY);
 
 	return class_entry;
 }

Zend/zend_compile.c

@@ -7918,6 +7918,11 @@ static void zend_compile_params(zend_ast *ast, zend_ast *return_type_ast, uint32
 			if (attributes_ast) {
 				zend_compile_attributes(
 					&prop->attributes, attributes_ast, 0, ZEND_ATTRIBUTE_TARGET_PROPERTY, ZEND_ATTRIBUTE_TARGET_PARAMETER);
+
+				zend_attribute *override_attribute = zend_get_attribute_str(prop->attributes, "override", sizeof("override")-1);
+				if (override_attribute) {
+					prop->flags |= ZEND_ACC_OVERRIDE;
+				}
 			}
 		}
 	}
@@ -8897,6 +8902,11 @@ static void zend_compile_prop_decl(zend_ast *ast, zend_ast *type_ast, uint32_t f
 
 		if (attr_ast) {
 			zend_compile_attributes(&info->attributes, attr_ast, 0, ZEND_ATTRIBUTE_TARGET_PROPERTY, 0);
+
+			zend_attribute *override_attribute = zend_get_attribute_str(info->attributes, "override", sizeof("override")-1);
+			if (override_attribute) {
+				info->flags |= ZEND_ACC_OVERRIDE;
+			}
 		}
 
 		CG(context).active_property_info_name = old_active_property_info_name;

Zend/zend_compile.h

@@ -254,7 +254,10 @@ typedef struct _zend_oparray_context {
 /* or IS_CONSTANT_VISITED_MARK                            |     |     |     */
 #define ZEND_CLASS_CONST_IS_CASE         (1 <<  6) /*     |     |     |  X  */
 /*                                                        |     |     |     */
-/* Property Flags (unused: 13...)                         |     |     |     */
+/* has #[\Override] attribute                             |     |     |     */
+#define ZEND_ACC_OVERRIDE                (1 << 28) /*     |  X  |  X  |     */
+/*                                                        |     |     |     */
+/* Property Flags (unused: 13-27,29...)                   |     |     |     */
 /* ===========                                            |     |     |     */
 /*                                                        |     |     |     */
 /* Promoted property / parameter                          |     |     |     */
@@ -393,9 +396,6 @@ typedef struct _zend_oparray_context {
 /* supports opcache compile-time evaluation (funcs)       |     |     |     */
 #define ZEND_ACC_COMPILE_TIME_EVAL       (1 << 27) /*     |  X  |     |     */
 /*                                                        |     |     |     */
-/* has #[\Override] attribute                             |     |     |     */
-#define ZEND_ACC_OVERRIDE                (1 << 28) /*     |  X  |     |     */
-/*                                                        |     |     |     */
 /* Has IS_PTR operands that needs special cleaning; same  |     |     |     */
 /* value as ZEND_ACC_OVERRIDE but override is for class   |     |     |     */
 /* methods and this is for the top level op array         |     |     |     */

Zend/zend_inheritance.c

@@ -1563,6 +1563,8 @@ static void do_inherit_property(zend_property_info *parent_info, zend_string *ke
 						ZSTR_VAL(key),
 						ZSTR_VAL(parent_info->ce->name));
 			}
+
+			child_info->flags &= ~ZEND_ACC_OVERRIDE;
 		}
 	} else {
 		zend_function **hooks = parent_info->hooks;
@@ -2315,13 +2317,11 @@ static void zend_do_implement_interfaces(zend_class_entry *ce, zend_class_entry
 
 void zend_inheritance_check_override(const zend_class_entry *ce)
 {
-	zend_function *f;
-
 	if (ce->ce_flags & ZEND_ACC_TRAIT) {
 		return;
 	}
 
-	ZEND_HASH_MAP_FOREACH_PTR(&ce->function_table, f) {
+	ZEND_HASH_MAP_FOREACH_PTR(&ce->function_table, zend_function *f) {
 		if (f->common.fn_flags & ZEND_ACC_OVERRIDE) {
 			ZEND_ASSERT(f->type != ZEND_INTERNAL_FUNCTION);
 
@@ -2332,14 +2332,17 @@ void zend_inheritance_check_override(const zend_class_entry *ce)
 		}
 	} ZEND_HASH_FOREACH_END();
 
-	if (ce->num_hooked_props) {
-		zend_property_info *prop;
-		ZEND_HASH_MAP_FOREACH_PTR(&ce->properties_info, prop) {
-			if (!prop->hooks) {
-				continue;
-			}
+	ZEND_HASH_MAP_FOREACH_PTR(&ce->properties_info, zend_property_info *prop) {
+		if (prop->flags & ZEND_ACC_OVERRIDE) {
+			zend_error_noreturn(
+				E_COMPILE_ERROR,
+				"%s::$%s has #[\\Override] attribute, but no matching parent property exists",
+				ZSTR_VAL(ce->name), zend_get_unmangled_property_name(prop->name));
+		}
+
+		if (prop->hooks) {
 			for (uint32_t i = 0; i < ZEND_PROPERTY_HOOK_COUNT; i++) {
-				f = prop->hooks[i];
+				zend_function *f = prop->hooks[i];
 				if (f && f->common.fn_flags & ZEND_ACC_OVERRIDE) {
 					ZEND_ASSERT(f->type != ZEND_INTERNAL_FUNCTION);
 
@@ -2349,8 +2352,8 @@ void zend_inheritance_check_override(const zend_class_entry *ce)
 						ZEND_FN_SCOPE_NAME(f), ZSTR_VAL(f->common.function_name));
 				}
 			}
-		} ZEND_HASH_FOREACH_END();
-	}
+		}
+	} ZEND_HASH_FOREACH_END();
 }