ReflectionProperty::isInitialized() should not trigger lazy object initialization

Author: jordikroon

ext/reflection/php_reflection.c

@@ -6289,6 +6289,22 @@ ZEND_METHOD(ReflectionProperty, isInitialized)
 			}
 		}
 
+		/* If this is an uninitialized lazy object, do not trigger initialization. */
+		if (ref->prop
+		    && !(prop_get_flags(ref) & ZEND_ACC_STATIC)
+		    && !(prop_get_flags(ref) & ZEND_ACC_VIRTUAL)
+		    && zend_object_is_lazy(Z_OBJ_P(object))
+		    && !zend_lazy_object_initialized(Z_OBJ_P(object))
+		) {
+		    zval *slot = OBJ_PROP(Z_OBJ_P(object), ref->prop->offset);
+
+		    if (Z_PROP_FLAG_P(slot) & IS_PROP_LAZY) {
+		        RETURN_FALSE;
+		    }
+
+		    RETURN_BOOL(!Z_ISUNDEF_P(slot));
+		}
+
 		const zend_class_entry *old_scope = EG(fake_scope);
 		EG(fake_scope) = intern->ce;
 		retval = Z_OBJ_HT_P(object)->has_property(Z_OBJ_P(object),

ext/reflection/tests/gh20830.phpt

@@ -0,0 +1,42 @@
+--TEST--
+GH-20830: ReflectionProperty::isInitialized() should not trigger lazy object initialization
+--FILE--
+<?php
+
+class TestClass {
+    public readonly int $id;
+    public string $name;
+}
+
+$rc = new ReflectionClass(TestClass::class);
+
+$obj = $rc->newLazyGhost(function ($ghost) {
+    $rp = new ReflectionProperty(TestClass::class, 'id');
+    $rp->setRawValueWithoutLazyInitialization($ghost, 123);
+    $ghost->name = 'initialized';
+    echo 'Ghost initialized' . PHP_EOL;
+});
+
+echo 'Created lazy ghost' . PHP_EOL;
+var_dump($rc->isUninitializedLazyObject($obj));
+
+echo 'Checking if $id is initialized...' . PHP_EOL;
+$rp = new ReflectionProperty(TestClass::class, 'id');
+var_dump($rp->isInitialized($obj));
+var_dump($rc->isUninitializedLazyObject($obj));
+
+echo 'Accessing $id value...' . PHP_EOL;
+$rp->getValue($obj);
+var_dump($rp->isInitialized($obj));
+var_dump($rc->isUninitializedLazyObject($obj));
+?>
+--EXPECT--
+Created lazy ghost
+bool(true)
+Checking if $id is initialized...
+bool(false)
+bool(true)
+Accessing $id value...
+Ghost initialized
+bool(true)
+bool(false)