Deprecate implicit dynamic properties

Writing to a proprety that hasn't been declared is deprecated,
unless the class uses the #[AllowDynamicProperties] attribute or
defines __get()/__set().

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

Author: nikic

UPGRADING

@@ -48,6 +48,16 @@ PHP 8.2 UPGRADE NOTES
 ========================================
 
 - Core:
+  . Creation of dynamic properties is deprecated, unless the class opts in by
+    using the #[AllowDynamicProperties] attribute. stdClass allows dynamic
+    properties. Usage of __get()/__set() is not affected by this change. A
+    dynamic properties deprecation warning can be addressed by:
+     - Declaring the property (preferred).
+     - Adding the #[AllowDynamicProperties] attribute to the class (which also
+       applies to all child classes).
+     - Using a WeakMap if you wish to associate additional data with an object
+       you do not own.
+
   . Callables that are not accepted by the $callable() syntax (but are accepted
     by call_user_func) are deprecated. In particular:
 

Zend/Optimizer/sccp.c

@@ -1101,7 +1101,9 @@ static void sccp_visit_instr(scdf_ctx *scdf, zend_op *opline, zend_ssa_op *ssa_o
 
 				/* Don't try to propagate assignments to (potentially) typed properties. We would
 				 * need to deal with errors and type conversions first. */
-				if (!var_info->ce || (var_info->ce->ce_flags & ZEND_ACC_HAS_TYPE_HINTS)) {
+				// TODO: Distinguish dynamic and declared property assignments here?
+				if (!var_info->ce || (var_info->ce->ce_flags & ZEND_ACC_HAS_TYPE_HINTS) ||
+						!(var_info->ce->ce_flags & ZEND_ACC_ALLOW_DYNAMIC_PROPERTIES)) {
 					SET_RESULT_BOT(result);
 					SET_RESULT_BOT(op1);
 					return;

Zend/Optimizer/zend_inference.c

@@ -4842,15 +4842,17 @@ ZEND_API bool zend_may_throw_ex(const zend_op *opline, const zend_ssa_op *ssa_op
 					return 1;
 				}
 
-				if (op_array->scope != ce && ce->default_properties_count) {
-					zend_property_info *prop_info =
-						zend_hash_find_ptr(&ce->properties_info, prop_name);
-					if (prop_info && (!(prop_info->flags & ZEND_ACC_PUBLIC)
-								|| ZEND_TYPE_IS_SET(prop_info->type))) {
+				zend_property_info *prop_info =
+					zend_hash_find_ptr(&ce->properties_info, prop_name);
+				if (prop_info) {
+					if (ZEND_TYPE_IS_SET(prop_info->type)) {
 						return 1;
 					}
+					return !(prop_info->flags & ZEND_ACC_PUBLIC)
+						&& prop_info->ce != op_array->scope;
+				} else {
+					return !(ce->ce_flags & ZEND_ACC_ALLOW_DYNAMIC_PROPERTIES);
 				}
-				return 0;
 			}
 			return 1;
 		case ZEND_ROPE_INIT:

Zend/tests/allow_dynamic_properties_on_interface.phpt

@@ -0,0 +1,11 @@
+--TEST--
+#[AllowDynamicProperties] cannot be applied to interface
+--FILE--
+<?php
+
+#[AllowDynamicProperties]
+interface Test {}
+
+?>
+--EXPECTF--
+Fatal error: Cannot apply #[AllowDynamicProperties] to interface in %s on line %d

Zend/tests/allow_dynamic_properties_on_trait.phpt

@@ -0,0 +1,11 @@
+--TEST--
+#[AllowDynamicProperties] cannot be applied to trait
+--FILE--
+<?php
+
+#[AllowDynamicProperties]
+trait Test {}
+
+?>
+--EXPECTF--
+Fatal error: Cannot apply #[AllowDynamicProperties] to trait in %s on line %d

Zend/tests/anon/003.phpt

@@ -4,7 +4,7 @@ reusing anonymous classes
 <?php
 while (@$i++<10) {
     var_dump(new class($i) {
-
+        public $i;
         public function __construct($i) {
             $this->i = $i;
         }

Zend/tests/assign_to_obj_001.phpt

@@ -8,6 +8,7 @@ function &a($i) {
 }
 
 class A {
+    public $a;
     public function test() {
         $this->a = a(1);
         unset($this->a);

Zend/tests/bug27268.phpt

@@ -2,6 +2,7 @@
 Bug #27268 (Bad references accentuated by clone)
 --FILE--
 <?php
+#[AllowDynamicProperties]
 class A
 {
     public function &getA()

Zend/tests/bug30162.phpt

@@ -2,6 +2,7 @@
 Bug #30162 (Catching exception in constructor couses lose of $this)
 --FILE--
 <?php
+#[AllowDynamicProperties]
 class FIIFO {
 
     public function __construct() {
@@ -11,6 +12,7 @@ class FIIFO {
 
 }
 
+#[AllowDynamicProperties]
 class hariCow extends FIIFO {
 
     public function __construct() {

Zend/tests/bug38779_1.phpt

@@ -4,6 +4,7 @@ Bug #38779 (engine crashes when require()'ing file with syntax error through use
 <?php
 
 class Loader {
+    public $context;
     private $position;
     private $data;
     public function stream_open($path, $mode, $options, &$opened_path)  {

Zend/tests/bug47343.phpt

@@ -4,6 +4,7 @@ Bug #47343 (gc_collect_cycles causes a segfault when called within a destructor
 <?php
 class A
 {
+    public $data = [];
     public function __destruct()
     {
         gc_collect_cycles();
@@ -20,10 +21,7 @@ class A
 
 class B
 {
-    public function __construct($A)
-    {
-        $this->A = $A;
-    }
+    public function __construct(public $A) {}
 
     public function __destruct()
     {

Zend/tests/bug49893.phpt

@@ -12,6 +12,7 @@ class A {
     }
 }
 class B {
+    public $a;
     function __construct() {
         $this->a = new A();
         throw new Exception("1");

Zend/tests/bug51822.phpt

@@ -12,6 +12,7 @@ class DestructableObject
 
 class DestructorCreator
 {
+    public $test;
     public function __destruct()
     {
         $this->test = new DestructableObject;

Zend/tests/bug54268.phpt

@@ -20,6 +20,7 @@ class DestructableObject
 }
 class DestructorCreator
 {
+        public $test;
         public function __destruct()
         {
                 $this->test = new DestructableObject;

Zend/tests/bug55305.phpt

@@ -2,6 +2,7 @@
 Bug #55305 (ref lost: 1st ref instantiated in class def, 2nd ref made w/o instantiating)
 --FILE--
 <?php
+#[AllowDynamicProperties]
 class Foo {
   var $foo = "test";
 }

Zend/tests/bug60536_001.phpt

@@ -12,6 +12,7 @@ class Y extends X {
           return ++$this->x;
       }
 }
+#[AllowDynamicProperties]
 class Z extends Y {
       function __construct() {
           return ++$this->x;

Zend/tests/bug60833.phpt

@@ -5,35 +5,30 @@ Bug #60833 (self, parent, static behave inconsistently case-sensitive)
 class A {
     static $x = "A";
     function testit() {
-        $this->v1 = new sELF;
-        $this->v2 = new SELF;
+        var_dump(new sELF);
+        var_dump(new SELF);
     }
 }
 
 class B extends A {
     static $x = "B";
     function testit() {
         PARENT::testit();
-        $this->v3 = new sELF;
-        $this->v4 = new PARENT;
-        $this->v4 = STATIC::$x;
+        var_dump(new sELF);
+        var_dump(new PARENT);
+        var_dump(STATIC::$x);
     }
 }
 $t = new B();
 $t->testit();
-var_dump($t);
 ?>
---EXPECTF--
-object(B)#%d (4) {
-  ["v1"]=>
-  object(A)#%d (0) {
-  }
-  ["v2"]=>
-  object(A)#%d (0) {
-  }
-  ["v3"]=>
-  object(B)#%d (0) {
-  }
-  ["v4"]=>
-  string(1) "B"
+--EXPECT--
+object(A)#2 (0) {
 }
+object(A)#2 (0) {
+}
+object(B)#2 (0) {
+}
+object(A)#2 (0) {
+}
+string(1) "B"

Zend/tests/bug63462.phpt

@@ -4,6 +4,7 @@ Test script to verify that magic methods should be called only once when accessi
 Marco Pivetta <[email protected]>
 --FILE--
 <?php
+#[AllowDynamicProperties]
 class Test {
     public    $publicProperty;
     protected $protectedProperty;

Zend/tests/bug64821.1.phpt

@@ -3,6 +3,7 @@ Bug #64821 Custom Exceptions crash when internal properties overridden (variatio
 --FILE--
 <?php
 
+#[AllowDynamicProperties]
 class a extends exception {
     public function __construct() {
         $this->message = NULL;

Zend/tests/bug64960.phpt

@@ -31,6 +31,10 @@ $a['waa'];
 --EXPECTF--
 Notice: ob_end_flush(): Failed to delete and flush buffer. No buffer to delete or flush in %sbug64960.php on line 3
 
+Deprecated: Creation of dynamic property Exception::$_trace is deprecated in %s on line %d
+
+Deprecated: Creation of dynamic property Exception::$_trace is deprecated in %s on line %d
+
 Fatal error: Uncaught Exception in %sbug64960.php:19
 Stack trace:
 #0 [internal function]: {closure}(8, 'ob_end_clean():...', '%s', 9)

Zend/tests/bug65911.phpt

@@ -6,6 +6,7 @@ class A {}
 
 class B
 {
+    public $foo;
     public function go()
     {
         $this->foo = 'bar';

Zend/tests/bug66609.phpt

@@ -10,6 +10,7 @@ class Bar {
         return $foo->foo;
     }
 }
+#[AllowDynamicProperties]
 class Foo {
     public function __get($x) {
         global $bar;

Zend/tests/bug69446.phpt

@@ -5,6 +5,7 @@ zend.enable_gc = 1
 --FILE--
 <?php
 $bar = NULL;
+#[AllowDynamicProperties]
 class bad {
     public function __destruct() {
         global $bar;

Zend/tests/bug70223.phpt

@@ -3,6 +3,9 @@ Bug #70223 (Incrementing value returned by magic getter)
 --FILE--
 <?php
 
+// Note that this actually writes to dynamic property A::$f.
+// Increment goes through __set(), not __get() by reference!
+#[AllowDynamicProperties]
 class A {
 
     private $foo = 0;

Zend/tests/bug70397.phpt

@@ -8,7 +8,9 @@ $f = function () {
     yield $this->value;
 };
 
-var_dump($f->call(new class {})->current());
+var_dump($f->call(new class {
+    public $value;
+})->current());
 
 ?>
 --EXPECT--

Zend/tests/bug70805.phpt

@@ -3,9 +3,11 @@ Bug #70805 (Segmentation faults whilst running Drupal 8 test suite)
 --FILE--
 <?php
 class A {
+    public $b;
 }
 
 class B {
+    public $a;
 }
 
 class C {

Zend/tests/bug70805_1.phpt

@@ -5,9 +5,11 @@ zend.enable_gc = 1
 --FILE--
 <?php
 class A {
+    public $b;
 }
 
 class B {
+    public $a;
 }
 
 class C {

Zend/tests/bug70805_2.phpt

@@ -5,9 +5,11 @@ zend.enable_gc = 1
 --FILE--
 <?php
 class A {
+    public $b;
 }
 
 class B {
+    public $a;
 }
 
 class C {

Zend/tests/bug71859.phpt

@@ -3,6 +3,7 @@ Bug #71859 (zend_objects_store_call_destructors operates on realloced memory, cr
 --FILE--
 <?php
 class constructs_in_destructor {
+  public $a;
   public function __destruct() {
     //We are now in zend_objects_store_call_destructors
     //This causes a realloc in zend_objects_store_put

Zend/tests/bug72101.phpt

@@ -26,6 +26,7 @@ class PHPUnit_Framework_MockObject_InvocationMocker {
 
 class PHPUnit_Framework_MockObject_Matcher {
     public $stub = null;
+    public $methodNameMatcher;
     public function invoked($invocation) {
         return $this->stub->invoke($invocation);
     }
@@ -77,10 +78,10 @@ $foo->bar($a, $b, $c);
 --EXPECTF--
 Fatal error: Uncaught Error: Class "DoesNotExists" not found in %s:%d
 Stack trace:
-#0 %sbug72101.php(8): {closure}(2, 'MethodCallbackB...', '%s', 8)
-#1 %sbug72101.php(27): PHPUnit_Framework_MockObject_Stub_ReturnCallback->invoke(Object(PHPUnit_Framework_MockObject_Invocation_Static))
-#2 %sbug72101.php(19): PHPUnit_Framework_MockObject_Matcher->invoked(Object(PHPUnit_Framework_MockObject_Invocation_Static))
-#3 %sbug72101.php(52): PHPUnit_Framework_MockObject_InvocationMocker->invoke(Object(PHPUnit_Framework_MockObject_Invocation_Static))
-#4 %sbug72101.php(72): Mock_MethodCallbackByReference_7b180d26->bar(0, 0, 0)
+#0 %sbug72101.php(%d): {closure}(2, 'MethodCallbackB...', '%s', 8)
+#1 %sbug72101.php(%d): PHPUnit_Framework_MockObject_Stub_ReturnCallback->invoke(Object(PHPUnit_Framework_MockObject_Invocation_Static))
+#2 %sbug72101.php(%d): PHPUnit_Framework_MockObject_Matcher->invoked(Object(PHPUnit_Framework_MockObject_Invocation_Static))
+#3 %sbug72101.php(%d): PHPUnit_Framework_MockObject_InvocationMocker->invoke(Object(PHPUnit_Framework_MockObject_Invocation_Static))
+#4 %sbug72101.php(%d): Mock_MethodCallbackByReference_7b180d26->bar(0, 0, 0)
 #5 {main}
-  thrown in %sbug72101.php on line 61
+  thrown in %sbug72101.php on line %d

Zend/tests/bug78010.phpt

@@ -5,6 +5,7 @@ memory_limit=2G
 --FILE--
 <?php
 
+#[AllowDynamicProperties]
 class foo
 {
     public function __construct()

Zend/tests/bug78340.phpt

@@ -4,9 +4,10 @@ Bug #78340: Include of stream wrapper not reading whole file
 <?php
 
 class lib {
+  public $context;
   public static $files= [];
 
-  private $bytes, $pos;
+  private $bytes, $pos, $ino;
 
   function stream_open($path, $mode, $options, $opened_path) {
     $this->bytes= self::$files[$path];