Fix ReflectionProperty::isInitialized() for hooked props

In zend_std_has_property with ZEND_PROPERTY_EXISTS, we'd just return true when
no get hook was present. However, this function is supposed to return false for
uninitialized properties. PROPERTY_EXISTS is somewhat of a misnomer. Virtual
properties continue to always return true, given there's no backing value to
check.

Fixes GH-15694
Closes GH-15822

NEWS

@@ -49,6 +49,8 @@ PHP                                                                        NEWS
 - Reflection:
   . Fixed bug GH-15718 (Segfault on ReflectionProperty::get{Hook,Hooks}() on
     dynamic properties). (DanielEScherzer)
+  . Fixed bug GH-15694 (ReflectionProperty::isInitialized() is incorrect for
+    hooked properties). (ilutov)
 
 - SOAP:
   . Fixed bug #61525 (SOAP functions require at least one space after HTTP

Zend/zend_object_handlers.c

@@ -2208,6 +2208,15 @@ found:
 		}
 	} else if (IS_HOOKED_PROPERTY_OFFSET(property_offset)) {
 		zend_function *get = prop_info->hooks[ZEND_PROPERTY_HOOK_GET];
+
+		if (has_set_exists == ZEND_PROPERTY_EXISTS) {
+			if (prop_info->flags & ZEND_ACC_VIRTUAL) {
+				return true;
+			}
+			property_offset = prop_info->offset;
+			goto try_again;
+		}
+
 		if (!get) {
 			if (prop_info->flags & ZEND_ACC_VIRTUAL) {
 				zend_throw_error(NULL, "Property %s::$%s is write-only",
@@ -2219,19 +2228,12 @@ found:
 			}
 		}
 
-		if (has_set_exists == ZEND_PROPERTY_EXISTS) {
-			return 1;
-		}
-
 		zval rv;
 		if (!zend_call_get_hook(prop_info, name, get, zobj, &rv)) {
 			if (EG(exception)) {
 				return 0;
 			}
 			property_offset = prop_info->offset;
-			if (!ZEND_TYPE_IS_SET(prop_info->type)) {
-				prop_info = NULL;
-			}
 			goto try_again;
 		}
 

ext/reflection/tests/property_hooks/ReflectionProperty_isInitialized.phpt

@@ -0,0 +1,56 @@
+--TEST--
+ReflectionProperty::isInitialized() on hooked properties
+--FILE--
+<?php
+
+class Test {
+    // Plain
+    public $p1;
+    public string $p2;
+    // Virtual
+    public $v1 { get => throw new Exception(); }
+    public $v2 { set { throw new Exception(); } }
+    // Backed
+    public $b1 { get => throw new Exception($this->b1); }
+    public string $b2 { get => throw new Exception($this->b2); }
+    public $b3 { set => throw new Exception(); }
+    public string $b4 { set => throw new Exception(); }
+}
+
+$test = new Test();
+$rc = new ReflectionClass(Test::class);
+foreach ($rc->getProperties() as $rp) {
+    echo $rp->getName(), "\n";
+    var_dump($rp->isInitialized($test));
+    try {
+        $rp->setRawValue($test, 42);
+    } catch (Error $e) {}
+    var_dump($rp->isInitialized($test));
+}
+
+?>
+--EXPECT--
+p1
+bool(true)
+bool(true)
+p2
+bool(false)
+bool(true)
+v1
+bool(true)
+bool(true)
+v2
+bool(true)
+bool(true)
+b1
+bool(true)
+bool(true)
+b2
+bool(false)
+bool(true)
+b3
+bool(true)
+bool(true)
+b4
+bool(false)
+bool(true)