Fixed bug #78632

I'm going for a very conservative fix here, where the previous
logic is restored for the case where an object is passed to
method_exists(). We might want to check against EG(scope) instead,
but this seems like a safer choice.

This means that behavior in PHP 7.4 changes only for
method_exists('C', 'privateMethodNotOnC'), which should be sensible.

NEWS

@@ -6,6 +6,8 @@ PHP                                                                        NEWS
   . Fixed bug #78614 (Does not compile with DTRACE anymore).
     (tz at FreeBSD dot org)
   . Fixed bug #78620 (Out of memory error). (cmb, Nikita)
+  . Fixed bug #78632 (method_exists() in php74 works differently from php73 in
+    checking priv. methods). (Nikita)
 
 - Pcntl:
   . Fixed bug #77335 (PHP is preventing SIGALRM from specifying SA_RESTART).

Zend/tests/bug50810.phpt

@@ -40,7 +40,7 @@ var_dump($example->propertyBarExists());
 
 ?>
 --EXPECT--
-bool(false)
+bool(true)
 bool(true)
 bool(true)
 bool(true)

Zend/zend_builtin_functions.c

@@ -1373,7 +1373,11 @@ ZEND_FUNCTION(method_exists)
 	zend_string_release_ex(lcname, 0);
 
 	if (func) {
-		RETURN_BOOL(!(func->common.fn_flags & ZEND_ACC_PRIVATE) || func->common.scope == ce);
+		/* Exclude shadow properties when checking a method on a specific class. Include
+		 * them when checking an object, as method_exists() generally ignores visibility.
+		 * TODO: Should we use EG(scope) for the object case instead? */
+		RETURN_BOOL(Z_TYPE_P(klass) == IS_OBJECT
+			|| !(func->common.fn_flags & ZEND_ACC_PRIVATE) || func->common.scope == ce);
 	}
 
 	if (Z_TYPE_P(klass) == IS_OBJECT) {

ext/standard/tests/class_object/method_exists_basic_001.phpt

@@ -68,10 +68,10 @@ Does C::non_existent exist? bool(false)
  ---(Using object)---
 Does C::inherit_pub exist? bool(true)
 Does C::inherit_prot exist? bool(true)
-Does C::inherit_priv exist? bool(false)
+Does C::inherit_priv exist? bool(true)
 Does C::inherit_static_pub exist? bool(true)
 Does C::inherit_static_prot exist? bool(true)
-Does C::inherit_static_priv exist? bool(false)
+Does C::inherit_static_priv exist? bool(true)
 Does C::pub exist? bool(true)
 Does C::prot exist? bool(true)
 Does C::priv exist? bool(true)