Classify object handlers are required/optional

Author: nikic

UPGRADING.INTERNALS

@@ -7,6 +7,7 @@ PHP 7.4 INTERNALS UPGRADE NOTES
   d. Removed zend_check_private()
   e. php_win32_error_to_msg() memory management
   f. get_properties_for() handler / Z_OBJDEBUG_P
+  g. Required object handlers
 
 2. Build system changes
   a. Abstract
@@ -98,6 +99,28 @@ PHP 7.4 INTERNALS UPGRADE NOTES
          // ...
          zend_release_properties(ht);
 
+  g. The following object handlers are now required (must be non-NULL):
+
+       * free_obj
+       * dtor_obj
+       * read_property
+       * write_property
+       * read_dimension
+       * write_dimension
+       * get_property_ptr_ptr
+       * has_property
+       * unset_property
+       * has_dimension
+       * unset_dimension
+       * get_properties
+       * get_method
+       * get_constructor
+       * get_class_name
+       * get_gc
+
+     It is recommended to initialize object handler structures by copying the
+     std object handlers and only overwriting those you want to change.
+
 ========================
 2. Build system changes
 ========================

Zend/zend_API.c

@@ -3114,7 +3114,7 @@ static zend_always_inline int zend_is_callable_check_func(int check_flags, zval
 				fcc->function_handler = zend_get_call_trampoline_func(ce_org, mname, 0);
 				call_via_handler = 1;
 				retval = 1;
-			} else if (fcc->object->handlers->get_method) {
+			} else {
 				fcc->function_handler = fcc->object->handlers->get_method(&fcc->object, mname, NULL);
 				if (fcc->function_handler) {
 					if (strict_class &&
@@ -3935,9 +3935,6 @@ ZEND_API void zend_update_property_ex(zend_class_entry *scope, zval *object, zen
 
 	EG(fake_scope) = scope;
 
-	if (!Z_OBJ_HT_P(object)->write_property) {
-		zend_error_noreturn(E_CORE_ERROR, "Property %s of class %s cannot be updated", ZSTR_VAL(name), ZSTR_VAL(Z_OBJCE_P(object)->name));
-	}
 	ZVAL_STR(&property, name);
 	Z_OBJ_HT_P(object)->write_property(object, &property, value, NULL);
 
@@ -3952,9 +3949,6 @@ ZEND_API void zend_update_property(zend_class_entry *scope, zval *object, const
 
 	EG(fake_scope) = scope;
 
-	if (!Z_OBJ_HT_P(object)->write_property) {
-		zend_error_noreturn(E_CORE_ERROR, "Property %s of class %s cannot be updated", name, ZSTR_VAL(Z_OBJCE_P(object)->name));
-	}
 	ZVAL_STRINGL(&property, name, name_length);
 	Z_OBJ_HT_P(object)->write_property(object, &property, value, NULL);
 	zval_ptr_dtor(&property);
@@ -3979,9 +3973,6 @@ ZEND_API void zend_unset_property(zend_class_entry *scope, zval *object, const c
 
 	EG(fake_scope) = scope;
 
-	if (!Z_OBJ_HT_P(object)->unset_property) {
-		zend_error_noreturn(E_CORE_ERROR, "Property %s of class %s cannot be unset", name, ZSTR_VAL(Z_OBJCE_P(object)->name));
-	}
 	ZVAL_STRINGL(&property, name, name_length);
 	Z_OBJ_HT_P(object)->unset_property(object, &property, 0);
 	zval_ptr_dtor(&property);
@@ -4143,10 +4134,6 @@ ZEND_API zval *zend_read_property_ex(zend_class_entry *scope, zval *object, zend
 
 	EG(fake_scope) = scope;
 
-	if (!Z_OBJ_HT_P(object)->read_property) {
-		zend_error_noreturn(E_CORE_ERROR, "Property %s of class %s cannot be read", ZSTR_VAL(name), ZSTR_VAL(Z_OBJCE_P(object)->name));
-	}
-
 	ZVAL_STR(&property, name);
 	value = Z_OBJ_HT_P(object)->read_property(object, &property, silent?BP_VAR_IS:BP_VAR_R, NULL, rv);
 

Zend/zend_builtin_functions.c

@@ -1338,7 +1338,7 @@ ZEND_FUNCTION(method_exists)
 	if (zend_hash_exists(&ce->function_table, lcname)) {
 		zend_string_release_ex(lcname, 0);
 		RETURN_TRUE;
-	} else if (Z_TYPE_P(klass) == IS_OBJECT && Z_OBJ_HT_P(klass)->get_method != NULL) {
+	} else if (Z_TYPE_P(klass) == IS_OBJECT) {
 		zend_object *obj = Z_OBJ_P(klass);
 		zend_function *func = Z_OBJ_HT_P(klass)->get_method(&obj, method_name, NULL);
 		if (func != NULL) {
@@ -1401,7 +1401,6 @@ ZEND_FUNCTION(property_exists)
 	ZVAL_STR(&property_z, property);
 
 	if (Z_TYPE_P(object) ==  IS_OBJECT &&
-		Z_OBJ_HANDLER_P(object, has_property) &&
 		Z_OBJ_HANDLER_P(object, has_property)(object, &property_z, 2, NULL)) {
 		RETURN_TRUE;
 	}