Ignore inheritance rules on private methods

Author: pmmaga

Zend/tests/method_argument_binding.phpt

@@ -24,7 +24,7 @@ class C extends B {
 (new C)->test();
 
 class D {
-    private final function method(&$x) {
+    private function method(&$x) {
         ++$x;
     }
 }

Zend/zend_compile.c

@@ -848,6 +848,9 @@ uint32_t zend_add_member_modifier(uint32_t flags, uint32_t new_flag) /* {{{ */
 			"Cannot use the final modifier on an abstract class member", 0);
 		return 0;
 	}
+	if ((new_flags & ZEND_ACC_PRIVATE) && (new_flags & ZEND_ACC_FINAL)) {
+		zend_error(E_COMPILE_WARNING, "Private methods are inherently final as they cannot be overridden by other classes");
+	}
 	return new_flags;
 }
 /* }}} */

Zend/zend_inheritance.c

@@ -179,7 +179,9 @@ static void do_inherit_parent_constructor(zend_class_entry *ce) /* {{{ */
 	}
 
 	if (ce->constructor) {
-		if (parent->constructor && UNEXPECTED(parent->constructor->common.fn_flags & ZEND_ACC_FINAL)) {
+		if (parent->constructor
+			&& !(parent->constructor->common.fn_flags & ZEND_ACC_PRIVATE)
+			&& UNEXPECTED(parent->constructor->common.fn_flags & ZEND_ACC_FINAL)) {
 			zend_error_noreturn(E_ERROR, "Cannot override final %s::%s() with %s::%s()",
 				ZSTR_VAL(parent->name), ZSTR_VAL(parent->constructor->common.function_name),
 				ZSTR_VAL(ce->name), ZSTR_VAL(ce->constructor->common.function_name));
@@ -810,6 +812,15 @@ static zend_always_inline inheritance_status do_inheritance_check_on_method_ex(z
 	uint32_t parent_flags = parent->common.fn_flags;
 	zend_function *proto;
 
+	if (UNEXPECTED((parent_flags & ZEND_ACC_PRIVATE) && !(parent_flags & ZEND_ACC_ABSTRACT))) {
+		if (!check_only) {
+			child->common.fn_flags |= ZEND_ACC_CHANGED;
+			child->common.prototype = NULL;
+		}
+		/* The parent method is private and not an abstract so we don't need to check any inheritance rules */
+		return INHERITANCE_SUCCESS;
+	}
+
 	if (!checked && UNEXPECTED(parent_flags & ZEND_ACC_FINAL)) {
 		if (check_only) {
 			return INHERITANCE_ERROR;
@@ -851,10 +862,6 @@ static zend_always_inline inheritance_status do_inheritance_check_on_method_ex(z
 		child->common.fn_flags |= ZEND_ACC_CHANGED;
 	}
 
-	if ((parent_flags & ZEND_ACC_PRIVATE) && !(parent_flags & ZEND_ACC_ABSTRACT)) {
-		return INHERITANCE_SUCCESS;
-	}
-
 	proto = parent->common.prototype ?
 		parent->common.prototype : parent;
 

tests/classes/clone_005.phpt

@@ -6,7 +6,7 @@ abstract class base {
   public $a = 'base';
 
   // disallow cloning once forever
-  final private function __clone() {}
+  final protected function __clone() {}
 }
 
 class test extends base {

tests/classes/inheritance_007.phpt

@@ -0,0 +1,50 @@
+--TEST--
+Ensure private methods with the same name are not checked for inheritance rules
+--FILE--
+<?php
+class A {
+    function callYourPrivates() {
+        $this->normalPrivate();
+        $this->finalPrivate();
+    }
+    function notOverridden_callYourPrivates() {
+        $this->normalPrivate();
+        $this->finalPrivate();
+    }
+    private function normalPrivate() {
+        echo __METHOD__ . PHP_EOL;
+    }
+    final private function finalPrivate() {
+        echo __METHOD__ . PHP_EOL;
+    }
+}
+class B extends A {
+    function callYourPrivates() {
+        $this->normalPrivate();
+        $this->finalPrivate();
+    }
+    private function normalPrivate() {
+        echo __METHOD__ . PHP_EOL;
+    }
+    final private function finalPrivate() {
+        echo __METHOD__ . PHP_EOL;
+    }
+}
+$a = new A();
+$a->callYourPrivates();
+$a->notOverridden_callYourPrivates();
+$b = new B();
+$b->callYourPrivates();
+$b->notOverridden_callYourPrivates();
+--EXPECTF--
+Warning: Private methods are inherently final as they cannot be overridden by other classes %s
+
+Warning: Private methods are inherently final as they cannot be overridden by other classes %s
+A::normalPrivate
+A::finalPrivate
+A::normalPrivate
+A::finalPrivate
+B::normalPrivate
+B::finalPrivate
+A::normalPrivate
+A::finalPrivate