Merge branch 'PHP-7.4'

* PHP-7.4:
  Fixed bug #78810

Author: nikic

Zend/tests/bug78810.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Bug #78810: RW fetches do not throw "uninitialized property" exception
+--FILE--
+<?php
+
+class Test {
+    public int $i;
+}
+
+$test = new Test;
+try {
+    $test->i++;
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    $test->i += 1;
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+Typed property Test::$i must not be accessed before initialization
+Typed property Test::$i must not be accessed before initialization

Zend/zend_object_handlers.c

@@ -1013,8 +1013,16 @@ ZEND_API zval *zend_std_get_property_ptr_ptr(zend_object *zobj, zend_string *nam
 			if (EXPECTED(!zobj->ce->__get) ||
 			    UNEXPECTED((*zend_get_property_guard(zobj, name)) & IN_GET)) {
 				if (UNEXPECTED(type == BP_VAR_RW || type == BP_VAR_R)) {
-					ZVAL_NULL(retval);
-					zend_error(E_WARNING, "Undefined property: %s::$%s", ZSTR_VAL(zobj->ce->name), ZSTR_VAL(name));
+					if (UNEXPECTED(prop_info)) {
+						zend_throw_error(NULL,
+							"Typed property %s::$%s must not be accessed before initialization",
+							ZSTR_VAL(prop_info->ce->name),
+							ZSTR_VAL(name));
+						retval = &EG(error_zval);
+					} else {
+						ZVAL_NULL(retval);
+						zend_error(E_WARNING, "Undefined property: %s::$%s", ZSTR_VAL(zobj->ce->name), ZSTR_VAL(name));
+					}
 				}
 			} else {
 				/* we do have getter - fail and let it try again with usual get/set */