[RFC] Property hooks

UPGRADING

@@ -215,6 +215,8 @@ PHP 8.4 UPGRADE NOTES
     RFC: https://wiki.php.net/rfc/new_without_parentheses
   . Added the #[\Deprecated] attribute.
     RFC: https://wiki.php.net/rfc/deprecated_attribute
+  . Implemented property hooks.
+    RFC: https://wiki.php.net/rfc/property-hooks
 
 - Curl:
   . curl_version() returns an additional feature_list value, which is an

Zend/Optimizer/compact_literals.c

@@ -197,6 +197,9 @@ void zend_optimizer_compact_literals(zend_op_array *op_array, zend_optimizer_ctx
 						LITERAL_INFO(opline->op2.constant, 2);
 					}
 					break;
+				case ZEND_INIT_PARENT_PROPERTY_HOOK_CALL:
+					LITERAL_INFO(opline->op1.constant, 1);
+					break;
 				case ZEND_CATCH:
 					LITERAL_INFO(opline->op1.constant, 2);
 					break;

Zend/Optimizer/optimize_func_calls.c

@@ -48,6 +48,7 @@ static void zend_delete_call_instructions(zend_op_array *op_array, zend_op *opli
 			case ZEND_INIT_STATIC_METHOD_CALL:
 			case ZEND_INIT_METHOD_CALL:
 			case ZEND_INIT_FCALL:
+			case ZEND_INIT_PARENT_PROPERTY_HOOK_CALL:
 				if (call == 0) {
 					MAKE_NOP(opline);
 					return;
@@ -169,12 +170,15 @@ void zend_optimize_func_calls(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 			case ZEND_INIT_METHOD_CALL:
 			case ZEND_INIT_FCALL:
 			case ZEND_NEW:
+			case ZEND_INIT_PARENT_PROPERTY_HOOK_CALL:
 				/* The argument passing optimizations are valid for prototypes as well,
 				 * as inheritance cannot change between ref <-> non-ref arguments. */
 				call_stack[call].func = zend_optimizer_get_called_func(
 					ctx->script, op_array, opline, &call_stack[call].is_prototype);
 				call_stack[call].try_inline =
-					!call_stack[call].is_prototype && opline->opcode != ZEND_NEW;
+					!call_stack[call].is_prototype
+					&& opline->opcode != ZEND_NEW
+					&& opline->opcode != ZEND_INIT_PARENT_PROPERTY_HOOK_CALL;
 				ZEND_FALLTHROUGH;
 			case ZEND_INIT_DYNAMIC_CALL:
 			case ZEND_INIT_USER_CALL:
@@ -212,6 +216,7 @@ void zend_optimize_func_calls(zend_op_array *op_array, zend_optimizer_ctx *ctx)
 						}
 					} else if (fcall->opcode == ZEND_INIT_STATIC_METHOD_CALL
 							|| fcall->opcode == ZEND_INIT_METHOD_CALL
+							|| fcall->opcode == ZEND_INIT_PARENT_PROPERTY_HOOK_CALL
 							|| fcall->opcode == ZEND_NEW) {
 						/* We don't have specialized opcodes for this, do nothing */
 					} else {

Zend/Optimizer/zend_call_graph.c

@@ -61,6 +61,7 @@ ZEND_API void zend_analyze_calls(zend_arena **arena, zend_script *script, uint32
 			case ZEND_INIT_FCALL:
 			case ZEND_INIT_METHOD_CALL:
 			case ZEND_INIT_STATIC_METHOD_CALL:
+			case ZEND_INIT_PARENT_PROPERTY_HOOK_CALL:
 				call_stack[call] = call_info;
 				func = zend_optimizer_get_called_func(
 					script, op_array, opline, &is_prototype);

Zend/Optimizer/zend_optimizer.c

@@ -974,6 +974,28 @@ zend_function *zend_optimizer_get_called_func(
 				}
 			}
 			break;
+		case ZEND_INIT_PARENT_PROPERTY_HOOK_CALL: {
+			zend_class_entry *scope = op_array->scope;
+			ZEND_ASSERT(scope != NULL);
+			if ((scope->ce_flags & ZEND_ACC_LINKED) && scope->parent) {
+				zend_class_entry *parent_scope = scope->parent;
+				zend_string *prop_name = Z_STR_P(CRT_CONSTANT(opline->op1));
+				zend_property_hook_kind hook_kind = opline->op2.num;
+				zend_property_info *prop_info = zend_get_property_info(parent_scope, prop_name, /* silent */ true);
+
+				if (prop_info
+					&& prop_info != ZEND_WRONG_PROPERTY_INFO
+					&& !(prop_info->flags & ZEND_ACC_PRIVATE)
+					&& prop_info->hooks) {
+					zend_function *fbc = prop_info->hooks[hook_kind];
+					if (fbc) {
+						*is_prototype = false;
+						return fbc;
+					}
+				}
+			}
+			break;
+		}
 		case ZEND_NEW:
 		{
 			zend_class_entry *ce = zend_optimizer_get_class_entry_from_op1(
@@ -1531,6 +1553,19 @@ void zend_foreach_op_array(zend_script *script, zend_op_array_func_t func, void
 				zend_foreach_op_array_helper(op_array, func, context);
 			}
 		} ZEND_HASH_FOREACH_END();
+
+		zend_property_info *property;
+		ZEND_HASH_MAP_FOREACH_PTR(&ce->properties_info, property) {
+			zend_function **hooks = property->hooks;
+			if (property->ce == ce && property->hooks) {
+				for (uint32_t i = 0; i < ZEND_PROPERTY_HOOK_COUNT; i++) {
+					zend_function *hook = hooks[i];
+					if (hook && hook->common.scope == ce) {
+						zend_foreach_op_array_helper(&hooks[i]->op_array, func, context);
+					}
+				}
+			}
+		} ZEND_HASH_FOREACH_END();
 	} ZEND_HASH_FOREACH_END();
 }
 

Zend/tests/alternative_offset_syntax_compile_error_in_const_expr.phpt

@@ -6,4 +6,4 @@ const FOO_COMPILE_ERROR = "BAR"{0};
 var_dump(FOO_COMPILE_ERROR);
 ?>
 --EXPECTF--
-Fatal error: Array and string offset access syntax with curly braces is no longer supported in %s on line 2
+Parse error: syntax error, unexpected token "{", expecting "," or ";" in %s on line %d

Zend/tests/alternative_offset_syntax_compile_error_outside_const_expr.phpt

@@ -6,4 +6,4 @@ $foo = 'BAR';
 var_dump($foo{0});
 ?>
 --EXPECTF--
-Fatal error: Array and string offset access syntax with curly braces is no longer supported in %s on line 3
+Parse error: syntax error, unexpected token "{", expecting ")" in %s on line %d

Zend/tests/alternative_offset_syntax_in_encaps_string.phpt

@@ -3,4 +3,4 @@ Alternative offset syntax should emit only E_COMPILE_ERROR in string interpolati
 --FILE--
 <?php "{$g{'h'}}"; ?>
 --EXPECTF--
-Fatal error: Array and string offset access syntax with curly braces is no longer supported in %s on line 1
+Parse error: syntax error, unexpected token "{", expecting "->" or "?->" or "[" in %s on line %d

Zend/tests/errmsg_037.phpt

@@ -10,4 +10,4 @@ class test {
 echo "Done\n";
 ?>
 --EXPECTF--
-Fatal error: Cannot use the abstract modifier on a property in %s on line %d
+Fatal error: Only hooked properties may be declared abstract in %s on line %d

Zend/tests/new_without_parentheses/unset_new.phpt

@@ -7,4 +7,4 @@ unset(new ArrayObject());
 
 ?>
 --EXPECTF--
-Parse error: syntax error, unexpected token ")", expecting "->" or "?->" or "{" or "[" in %s on line %d
+Parse error: syntax error, unexpected token ")", expecting "->" or "?->" or "[" in %s on line %d

Zend/tests/property_hooks/abstract_hook.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Abstract hooks compile successfully
+--FILE--
+<?php
+
+abstract class A {
+    public abstract $prop {
+        get;
+        set {}
+    }
+}
+
+class B extends A {
+    public $prop {
+        get {}
+    }
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/tests/property_hooks/abstract_hook_in_non_abstract_class.phpt

@@ -0,0 +1,15 @@
+--TEST--
+Abstract hooks in non-abstract class gives an error
+--FILE--
+<?php
+
+class Test {
+    public abstract $prop {
+        get;
+        set {}
+    }
+}
+
+?>
+--EXPECTF--
+Fatal error: Class Test contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (Test::$prop::get) in %s on line %d

Zend/tests/property_hooks/abstract_hook_not_implemented.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Abstract hooks that are not implemented throw an error
+--FILE--
+<?php
+
+abstract class A {
+    public abstract $prop {
+        get;
+        set {}
+    }
+}
+
+class B extends A {}
+
+?>
+--EXPECTF--
+Fatal error: Class B contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (A::$prop::get) in %s on line %d

Zend/tests/property_hooks/abstract_prop_hooks.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Explicit hooked property satisfies abstract property
+--FILE--
+<?php
+
+abstract class A {
+    abstract public $prop { get; set; }
+}
+
+class B extends A {
+    public $prop { get {} set {} }
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/tests/property_hooks/abstract_prop_not_implemented.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Abstract property not implemented throws an error
+--FILE--
+<?php
+
+class A {
+    abstract public $prop { get; set; }
+}
+
+class B extends A {}
+
+?>
+--EXPECTF--
+Fatal error: Class A contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods (A::$prop::get, A::$prop::set) in %s on line %d

Zend/tests/property_hooks/abstract_prop_plain.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Plain property satisfies abstract property
+--FILE--
+<?php
+
+abstract class A {
+    abstract public $prop { get; set; }
+}
+
+class B extends A {
+    public $prop;
+}
+
+?>
+===DONE===
+--EXPECT--
+===DONE===

Zend/tests/property_hooks/abstract_prop_without_hooks.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Abstract property without hook is illegal
+--FILE--
+<?php
+
+class C {
+    abstract public $prop;
+}
+
+?>
+--EXPECTF--
+Fatal error: Only hooked properties may be declared abstract in %s on line %d

Zend/tests/property_hooks/array_access.phpt

@@ -0,0 +1,49 @@
+--TEST--
+Array offset on ArrayAccess object in virtual property is allowed
+--FILE--
+<?php
+
+class Collection implements ArrayAccess {
+    public function offsetExists(mixed $offset): bool {
+        echo __METHOD__ . "\n";
+        return true;
+    }
+
+    public function offsetGet(mixed $offset): mixed {
+        echo __METHOD__ . "\n";
+        return true;
+    }
+
+    public function offsetSet(mixed $offset, mixed $value): void {
+        echo __METHOD__ . "\n";
+    }
+
+    public function offsetUnset(mixed $offset): void {
+        echo __METHOD__ . "\n";
+    }
+}
+
+class C {
+    public function __construct(
+        public Collection $collection = new Collection(),
+    ) {}
+    public $prop {
+        get => $this->collection;
+    }
+}
+
+$c = new C();
+var_dump($c->prop['foo']);
+var_dump($c->prop[] = 'foo');
+var_dump(isset($c->prop['foo']));
+unset($c->prop['foo']);
+
+?>
+--EXPECT--
+Collection::offsetGet
+bool(true)
+Collection::offsetSet
+string(3) "foo"
+Collection::offsetExists
+bool(true)
+Collection::offsetUnset

Zend/tests/property_hooks/ast_printing.phpt

@@ -0,0 +1,45 @@
+--TEST--
+Hook AST printing
+--FILE--
+<?php
+
+try {
+    assert(false && new class {
+        public $prop1 { get; set; }
+        public $prop2 {
+            get {
+                return parent::$prop1::get();
+            }
+            final set {
+                echo 'Foo';
+                $this->prop1 = 42;
+            }
+        }
+        public $prop3 = 1 {
+            get => 42;
+        }
+    });
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+assert(false && new class {
+    public $prop1 {
+        get;
+        set;
+    }
+    public $prop2 {
+        get {
+            return parent::$prop1::get();
+        }
+        final set {
+            echo 'Foo';
+            $this->prop1 = 42;
+        }
+    }
+    public $prop3 = 1 {
+        get => 42;
+    }
+})