[RFC] Allow #[\Deprecated] on interfaces

Zend/tests/attributes/delayed_target_validation/validator_Deprecated.phpt

@@ -3,10 +3,6 @@
 --FILE--
 <?php
 
-#[DelayedTargetValidation]
-#[Deprecated]
-interface DemoInterface {}
-
 #[DelayedTargetValidation]
 #[Deprecated]
 class DemoClass {}
@@ -16,7 +12,6 @@ class DemoClass {}
 enum DemoEnum {}
 
 $cases = [
-	new ReflectionClass('DemoInterface'),
 	new ReflectionClass('DemoClass'),
 	new ReflectionClass('DemoEnum'),
 ];
@@ -35,39 +30,6 @@ foreach ($cases as $r) {
 ?>
 --EXPECTF--
 ********************
-Interface [ <user> interface DemoInterface ] {
-  @@ %s %d-%d
-
-  - Constants [0] {
-  }
-
-  - Static properties [0] {
-  }
-
-  - Static methods [0] {
-  }
-
-  - Properties [0] {
-  }
-
-  - Methods [0] {
-  }
-}
-
-array(2) {
-  [0]=>
-  object(ReflectionAttribute)#%d (1) {
-    ["name"]=>
-    string(23) "DelayedTargetValidation"
-  }
-  [1]=>
-  object(ReflectionAttribute)#%d (1) {
-    ["name"]=>
-    string(10) "Deprecated"
-  }
-}
-Error: Cannot apply #[\Deprecated] to interface DemoInterface
-********************
 Class [ <user> class DemoClass ] {
   @@ %s %d-%d
 

Zend/tests/attributes/delayed_target_validation/with_Deprecated.phpt

@@ -48,6 +48,12 @@ class WithDeprecatedTrait {
 	use DeprecatedTrait;
 }
 
+#[DelayedTargetValidation]
+#[Deprecated] // Does something here
+interface DeprecatedInterface {}
+
+class ImplementsDeprecatedInterface implements DeprecatedInterface {}
+
 #[DelayedTargetValidation]
 #[Deprecated] // Does something here
 function demoFn() {
@@ -70,6 +76,8 @@ var_dump(GLOBAL_CONST);
 ?>
 --EXPECTF--
 Deprecated: Trait DeprecatedTrait used by WithDeprecatedTrait is deprecated in %s on line %d
+
+Deprecated: Interface DeprecatedInterface implemented by ImplementsDeprecatedInterface is deprecated in %s on line %d
 Got: example
 
 Deprecated: Method DemoClass::printVal() is deprecated in %s on line %d

Zend/tests/attributes/deprecated/interfaces/basic.phpt

@@ -0,0 +1,34 @@
+--TEST--
+#[\Deprecated]: Basic interface deprecation
+--FILE--
+<?php
+
+#[\Deprecated("please do not use")]
+interface DemoInterface1 {}
+
+#[\Deprecated("will be removed in 3.0", since: "2.7")]
+interface DemoInterface2 {}
+
+#[\Deprecated(message: "going away")]
+interface DemoInterface3 {}
+
+#[\Deprecated(since: "3.5")]
+interface DemoInterface4 {}
+
+class DemoClass implements
+	DemoInterface1,
+	DemoInterface2,
+	DemoInterface3,
+	DemoInterface4
+{
+}
+
+?>
+--EXPECTF--
+Deprecated: Interface DemoInterface1 implemented by DemoClass is deprecated, please do not use in %s on line %d
+
+Deprecated: Interface DemoInterface2 implemented by DemoClass is deprecated since 2.7, will be removed in 3.0 in %s on line %d
+
+Deprecated: Interface DemoInterface3 implemented by DemoClass is deprecated, going away in %s on line %d
+
+Deprecated: Interface DemoInterface4 implemented by DemoClass is deprecated since 3.5 in %s on line %d

Zend/tests/attributes/deprecated/interfaces/extending_deprecated_interface.phpt

@@ -0,0 +1,31 @@
+--TEST--
+#[\Deprecated]: Interfaces extending deprecated interfaces trigger warnings
+--FILE--
+<?php
+
+#[\Deprecated("please do not use")]
+interface DemoInterface1 {}
+
+#[\Deprecated("will be removed in 3.0", since: "2.7")]
+interface DemoInterface2 {}
+
+#[\Deprecated(message: "going away")]
+interface DemoInterface3 {}
+
+#[\Deprecated(since: "3.5")]
+interface DemoInterface4 {}
+
+interface ExtendsDemo1 extends DemoInterface1 {}
+interface ExtendsDemo2 extends DemoInterface2 {}
+interface ExtendsDemo3 extends DemoInterface3 {}
+interface ExtendsDemo4 extends DemoInterface4 {}
+
+?>
+--EXPECTF--
+Deprecated: Interface DemoInterface1 extended by ExtendsDemo1 is deprecated, please do not use in %s on line %d
+
+Deprecated: Interface DemoInterface2 extended by ExtendsDemo2 is deprecated since 2.7, will be removed in 3.0 in %s on line %d
+
+Deprecated: Interface DemoInterface3 extended by ExtendsDemo3 is deprecated, going away in %s on line %d
+
+Deprecated: Interface DemoInterface4 extended by ExtendsDemo4 is deprecated since 3.5 in %s on line %d

Zend/tests/attributes/deprecated/interfaces/implements_child.phpt

@@ -0,0 +1,15 @@
+--TEST--
+#[\Deprecated]: Implementing a child of a deprecated interface
+--FILE--
+<?php
+
+#[\Deprecated("please do not use")]
+interface BaseInterface {}
+
+interface ChildInterface extends BaseInterface {}
+
+class DemoClass implements ChildInterface {}
+
+?>
+--EXPECTF--
+Deprecated: Interface BaseInterface extended by ChildInterface is deprecated, please do not use in %s on line %d

Zend/tests/attributes/deprecated/interfaces/implements_interface_and_child.phpt

@@ -0,0 +1,17 @@
+--TEST--
+#[\Deprecated]: Implementing a deprecated interface and a child of it
+--FILE--
+<?php
+
+#[\Deprecated("please do not use")]
+interface BaseInterface {}
+
+interface ChildInterface extends BaseInterface {}
+
+class DemoClass implements BaseInterface, ChildInterface {}
+
+?>
+--EXPECTF--
+Deprecated: Interface BaseInterface extended by ChildInterface is deprecated, please do not use in %s on line %d
+
+Deprecated: Interface BaseInterface implemented by DemoClass is deprecated, please do not use in %s on line %d

Zend/tests/attributes/deprecated/interfaces/inherited_interface_implementation.phpt

@@ -0,0 +1,15 @@
+--TEST--
+#[\Deprecated]: Parent class implements deprecated interface, child class inherits
+--FILE--
+<?php
+
+#[\Deprecated("please do not use")]
+interface DemoInterface {}
+
+class Base implements DemoInterface {}
+
+class Child extends Base {}
+
+?>
+--EXPECTF--
+Deprecated: Interface DemoInterface implemented by Base is deprecated, please do not use in %s on line %d

Zend/tests/attributes/deprecated/interfaces/inherited_manual_interface_implementation.phpt

@@ -0,0 +1,17 @@
+--TEST--
+#[\Deprecated]: Parent class implements deprecated interface, child class inherits and also implements
+--FILE--
+<?php
+
+#[\Deprecated("please do not use")]
+interface DemoInterface {}
+
+class Base implements DemoInterface {}
+
+class Child extends Base implements DemoInterface {}
+
+?>
+--EXPECTF--
+Deprecated: Interface DemoInterface implemented by Base is deprecated, please do not use in %s on line %d
+
+Deprecated: Interface DemoInterface implemented by Child is deprecated, please do not use in %s on line %d

Zend/tests/attributes/deprecated/interfaces/throwing_error_handler.phpt

@@ -0,0 +1,23 @@
+--TEST--
+#[\Deprecated]: Deprecation converted to ErrorException does not break
+--FILE--
+<?php
+
+function my_error_handler(int $errno, string $errstr, ?string $errfile = null, ?int $errline = null) {
+	throw new \ErrorException($errstr, 0, $errno, $errfile, $errline);
+}
+
+set_error_handler('my_error_handler');
+
+#[\Deprecated]
+interface DemoInterface {}
+
+class DemoClass implements DemoInterface {}
+
+?>
+--EXPECTF--
+Fatal error: Uncaught ErrorException: Interface DemoInterface implemented by DemoClass is deprecated in %s:%d
+Stack trace:
+#0 %s(%d): my_error_handler(16384, 'Interface DemoI...', '%s', 12)
+#1 {main}
+  thrown in %s on line %d

Zend/tests/attributes/deprecated/interfaces/tool_comparison.phpt

@@ -0,0 +1,25 @@
+--TEST--
+#[\Deprecated]: Interface deprecation RFC example
+--FILE--
+<?php
+
+#[\Deprecated]
+interface BaseInterface {}
+
+interface ChildInterface extends BaseInterface {}
+
+class ImplementsBase implements BaseInterface {}
+
+class ImplementsBoth implements BaseInterface, ChildInterface {}
+
+class ImplementsChild implements ChildInterface {}
+
+class ExtendsBaseImplementor extends ImplementsBase {}
+
+?>
+--EXPECTF--
+Deprecated: Interface BaseInterface extended by ChildInterface is deprecated in %s on line %d
+
+Deprecated: Interface BaseInterface implemented by ImplementsBase is deprecated in %s on line %d
+
+Deprecated: Interface BaseInterface implemented by ImplementsBoth is deprecated in %s on line %d

Zend/tests/attributes/deprecated/interfaces/type_okay.phpt

@@ -0,0 +1,35 @@
+--TEST--
+#[\Deprecated]: Instanceof, type checking, etc. for deprecated interfaces are okay
+--FILE--
+<?php
+
+#[\Deprecated("please do not use")]
+interface DemoInterface {}
+
+class Identity {
+	public static function identity(
+		DemoInterface $in
+	): DemoInterface {
+		return $in;
+	}
+}
+
+class ImplementsDemo implements DemoInterface {};
+
+$instance = new ImplementsDemo();
+
+var_dump(is_a(ImplementsDemo::class, DemoInterface::class, true));
+var_dump(is_a($instance, DemoInterface::class));
+var_dump(is_subclass_of(Implementsdemo::class, DemoInterface::class, true));
+var_dump(is_subclass_of($instance, DemoInterface::class));
+var_dump($instance === Identity::identity($instance));
+var_dump($instance instanceof DemoInterface);
+?>
+--EXPECTF--
+Deprecated: Interface DemoInterface implemented by ImplementsDemo is deprecated, please do not use in %s on line %d
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)

Zend/zend_attributes.c

@@ -118,7 +118,7 @@ static zend_string *validate_deprecated(
 		/* Being used for a method or something, validation does not apply */
 		return NULL;
 	}
-	if (!(scope->ce_flags & ZEND_ACC_TRAIT)) {
+	if (!(scope->ce_flags & (ZEND_ACC_TRAIT|ZEND_ACC_INTERFACE))) {
 		const char *type = zend_get_object_type_case(scope, false);
 		return zend_strpprintf(0, "Cannot apply #[\\Deprecated] to %s %s", type, ZSTR_VAL(scope->name));
 	}

Zend/zend_execute.c

@@ -2032,6 +2032,43 @@ ZEND_API ZEND_COLD void zend_use_of_deprecated_trait(
 	zend_string_release(message_suffix);
 }
 
+static ZEND_COLD void zend_deprecated_interface_action(
+	zend_class_entry *iface,
+	const zend_string *by,
+	const char *action
+) {
+	zend_string *message_suffix = ZSTR_EMPTY_ALLOC();
+
+	if (get_deprecation_suffix_from_attribute(iface->attributes, iface, &message_suffix) == FAILURE) {
+		return;
+	}
+
+	int code = iface->type == ZEND_INTERNAL_CLASS ? E_DEPRECATED : E_USER_DEPRECATED;
+
+	zend_error_unchecked(code, "Interface %s %s by %s is deprecated%S",
+		ZSTR_VAL(iface->name),
+		action,
+		ZSTR_VAL(by),
+		message_suffix
+	);
+
+	zend_string_release(message_suffix);
+}
+
+ZEND_API ZEND_COLD void zend_implementation_of_deprecated_interface(
+	zend_class_entry *iface,
+	const zend_string *implemented_by
+) {
+	zend_deprecated_interface_action(iface, implemented_by, "implemented");
+}
+
+ZEND_API ZEND_COLD void zend_extending_deprecated_interface(
+	zend_class_entry *iface,
+	const zend_string *extended_by
+) {
+	zend_deprecated_interface_action(iface, extended_by, "extended");
+}
+
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_false_to_array_deprecated(void)
 {
 	zend_error(E_DEPRECATED, "Automatic conversion of false to array is deprecated");

Zend/zend_execute.h

@@ -66,6 +66,8 @@ ZEND_API ZEND_COLD void ZEND_FASTCALL zend_nodiscard_function(const zend_functio
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_deprecated_class_constant(const zend_class_constant *c, const zend_string *constant_name);
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_deprecated_constant(const zend_constant *c, const zend_string *constant_name);
 ZEND_API ZEND_COLD void zend_use_of_deprecated_trait(zend_class_entry *trait, const zend_string *used_by);
+ZEND_API ZEND_COLD void zend_implementation_of_deprecated_interface(zend_class_entry *iface, const zend_string *implemented_by);
+ZEND_API ZEND_COLD void zend_extending_deprecated_interface(zend_class_entry *iface, const zend_string *extended_by);
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_false_to_array_deprecated(void);
 ZEND_COLD void ZEND_FASTCALL zend_param_must_be_ref(const zend_function *func, uint32_t arg_num);
 ZEND_API ZEND_COLD void ZEND_FASTCALL zend_use_resource_as_offset(const zval *dim);

Zend/zend_inheritance.c

@@ -3557,6 +3557,17 @@ ZEND_API zend_class_entry *zend_do_link_class(zend_class_entry *ce, zend_string
 				free_alloca(traits_and_interfaces, use_heap);
 				return NULL;
 			}
+			if (UNEXPECTED(iface->ce_flags & ZEND_ACC_DEPRECATED)) {
+				if (ce->ce_flags & ZEND_ACC_INTERFACE) {
+					zend_extending_deprecated_interface(iface, ce->name);
+				} else {
+					zend_implementation_of_deprecated_interface(iface, ce->name);
+				}
+				if (UNEXPECTED(EG(exception))) {
+					free_alloca(traits_and_interfaces, use_heap);
+					return NULL;
+				}
+			}
 			traits_and_interfaces[ce->num_traits + i] = iface;
 			if (iface) {
 				UPDATE_IS_CACHEABLE(iface);