build/gen_stub: support asymmetric visibility modifiers. (#21773)

Emit ZEND_ACC_PUBLIC_SET / PROTECTED_SET / PRIVATE_SET from the
corresponding Modifiers::*_SET flags in generated arginfo, gated
to PHP 8.4+ where asymmetric visibility was introduced. Previously
private(set) and friends in stubs parsed without error but produced
no set-visibility flag.

@readonly on DOM property stubs was documentation only and did not
translate to any runtime flag, so reflection reported the properties
as writable while the write_property handler threw on assignment.
Declaring them public private(set) lets the engine reject external
writes via the normal visibility check and lets ReflectionProperty::
isWritable() answer honestly.

After converting virtual properties from @readonly to private(set),
dom_write_property still threw a readonly-modification error. Since
the handler replaces zend_std_write_property, the engine's own
asymmetric-visibility check is bypassed on the write path, so the
DOM handler now raises it explicitly via
zend_asymmetric_visibility_property_modification_error() when the
caller lacks set access. The readonly error is kept as a fallback.

Author: devnexen

build/gen_stub.php

@@ -2354,7 +2354,17 @@ protected function getFlagsByPhpVersion(): VersionFlags
             $flags = "ZEND_ACC_PRIVATE";
         }
 
-        return new VersionFlags([$flags]);
+        $versionFlags = new VersionFlags([$flags]);
+
+        if ($this->flags & Modifiers::PUBLIC_SET) {
+            $versionFlags->addForVersionsAbove("ZEND_ACC_PUBLIC_SET", PHP_84_VERSION_ID);
+        } elseif ($this->flags & Modifiers::PROTECTED_SET) {
+            $versionFlags->addForVersionsAbove("ZEND_ACC_PROTECTED_SET", PHP_84_VERSION_ID);
+        } elseif ($this->flags & Modifiers::PRIVATE_SET) {
+            $versionFlags->addForVersionsAbove("ZEND_ACC_PRIVATE_SET", PHP_84_VERSION_ID);
+        }
+
+        return $versionFlags;
     }
 
     protected function getTypeCode(string $variableLikeName, string &$code): string
@@ -2450,6 +2460,17 @@ protected function addModifiersToFieldSynopsis(DOMDocument $doc, DOMElement $fie
             $fieldsynopsisElement->appendChild(new DOMText("\n$indentation"));
             $fieldsynopsisElement->appendChild($doc->createElement("modifier", "private"));
         }
+
+        if ($this->flags & Modifiers::PUBLIC_SET) {
+            $fieldsynopsisElement->appendChild(new DOMText("\n$indentation"));
+            $fieldsynopsisElement->appendChild($doc->createElement("modifier", "public(set)"));
+        } elseif ($this->flags & Modifiers::PROTECTED_SET) {
+            $fieldsynopsisElement->appendChild(new DOMText("\n$indentation"));
+            $fieldsynopsisElement->appendChild($doc->createElement("modifier", "protected(set)"));
+        } elseif ($this->flags & Modifiers::PRIVATE_SET) {
+            $fieldsynopsisElement->appendChild(new DOMText("\n$indentation"));
+            $fieldsynopsisElement->appendChild($doc->createElement("modifier", "private(set)"));
+        }
     }
 
 }

ext/dom/php_dom.c

@@ -412,11 +412,6 @@ zval *dom_write_property(zend_object *object, zend_string *name, zval *value, vo
 	const dom_prop_handler *hnd = dom_get_prop_handler(obj, name, cache_slot);
 
 	if (hnd) {
-		if (UNEXPECTED(!hnd->write_func)) {
-			zend_readonly_property_modification_error_ex(ZSTR_VAL(object->ce->name), ZSTR_VAL(name));
-			return &EG(error_zval);
-		}
-
 		zend_property_info *prop = NULL;
 		if (cache_slot) {
 			ZEND_ASSERT(*cache_slot == obj->prop_handler);
@@ -429,6 +424,16 @@ zval *dom_write_property(zend_object *object, zend_string *name, zval *value, vo
 			}
 		}
 
+		if (UNEXPECTED(!hnd->write_func)) {
+			if (prop && (prop->flags & ZEND_ACC_PPP_SET_MASK) &&
+			    !zend_asymmetric_property_has_set_access(prop)) {
+				zend_asymmetric_visibility_property_modification_error(prop, "modify");
+			} else {
+				zend_readonly_property_modification_error_ex(ZSTR_VAL(object->ce->name), ZSTR_VAL(name));
+			}
+			return &EG(error_zval);
+		}
+
 		ZEND_ASSERT(prop && ZEND_TYPE_IS_SET(prop->type));
 		zval tmp;
 		ZVAL_COPY(&tmp, value);