fix(custom-elements): honor owner registries during parser construction

moli-renderer-v8/src/custom_elements/parser_handoff.rs

@@ -18,7 +18,6 @@ pub(crate) fn create_and_construct_parser_custom_element_direct_for_document(
     scope: &mut v8::PinScope<'_, '_>,
     host_ptr: *mut JsContextHost,
     document_handle: DomHandle,
-    document_has_body: bool,
     local_name: &str,
     namespace: &str,
     prefix: Option<&str>,
@@ -29,7 +28,6 @@ pub(crate) fn create_and_construct_parser_custom_element_direct_for_document(
     let definition_match = lookup_parser_custom_element_definition_for_token(
         host_ptr,
         document_handle,
-        document_has_body,
         local_name,
         namespace,
         token_attributes,

moli-renderer-v8/src/custom_elements/parser_handoff_definition.rs

@@ -16,7 +16,6 @@ pub(super) struct ParserCustomElementDefinitionMatch {
 pub(super) fn lookup_parser_custom_element_definition_for_token(
     host_ptr: *mut JsContextHost,
     document_handle: DomHandle,
-    document_has_body: bool,
     local_name: &str,
     namespace: &str,
     token_attributes: &[Attribute],
@@ -25,9 +24,6 @@ pub(super) fn lookup_parser_custom_element_definition_for_token(
     if namespace != XHTML_NS {
         return None;
     }
-    if !document_has_body {
-        return None;
-    }
     let host = unsafe { &*host_ptr };
     let document_default =
         host.default_custom_element_registry_association_for_document(document_handle);

moli-renderer-v8/src/document_runtime/document_write.rs

@@ -337,15 +337,11 @@ impl ParserElementCreationConsumer for DocumentWriteParserMutationOwner<'_, '_,
         &mut self,
         request: ParserElementCreationRequest<'_>,
     ) -> Option<DomHandle> {
-        let document_has_body = self
-            .document_body_handle_for_document(request.document_handle)
-            .is_some();
         let runtime = &mut *self.runtime;
         custom_elements::create_and_construct_parser_custom_element_direct_for_document(
             self.scope,
             self.host_ptr,
             request.document_handle,
-            document_has_body,
             request.local_name,
             request.namespace,
             request.prefix,

moli-renderer-v8/src/runtime/phase_one/parser_turn.rs

@@ -375,14 +375,10 @@ impl ParserElementCreationConsumer for PhaseOneParserOwner<'_> {
         &mut self,
         request: ParserElementCreationRequest<'_>,
     ) -> Option<NativeNodeId> {
-        let document_has_body = self
-            .document_body_handle_for_document(request.document_handle)
-            .is_some();
         self.vm
             .create_and_construct_parser_custom_element_direct_in_default_context(
                 request.construction,
                 request.document_handle,
-                document_has_body,
                 request.local_name,
                 request.namespace,
                 request.prefix,

moli-renderer-v8/src/script_vm.rs

@@ -4733,7 +4733,6 @@ impl ScriptVm {
         &mut self,
         construction: &moli_dom::native::ParserConstruction,
         document_handle: DomHandle,
-        document_has_body: bool,
         local_name: &str,
         namespace: &str,
         prefix: Option<&str>,
@@ -4758,7 +4757,6 @@ impl ScriptVm {
                         scope,
                         host_ptr,
                         document_handle,
-                        document_has_body,
                         local_name,
                         namespace,
                         prefix,

moli-renderer-v8/src/script_vm/tests/dom_elements/custom_elements/detached_documents_and_reactions.rs

@@ -2082,3 +2082,77 @@ async fn child_document_write_custom_element_reaction_queue_wpt_shape() {
 
     assert_eq!(result, expected);
 }
+
+#[test]
+fn child_document_write_constructs_predefined_custom_elements_without_a_body() {
+    let mut vm = new_storage_test_vm("https://document-write-custom-elements.test/");
+
+    vm.eval(
+        r#"
+            (() => {
+              const target = document.body || document.documentElement || document;
+              window.__writeCustomElementFrames = ["write", "writeln"].map(() => {
+                const frame = document.createElement("iframe");
+                target.appendChild(frame);
+                frame.srcdoc = "";
+                return frame;
+              });
+              return "scheduled";
+            })()
+            "#,
+    )
+    .expect("child document.write predefined custom element setup should evaluate");
+    vm.drain_pending_child_frame_work_for_test();
+
+    let result = vm
+        .eval(
+            r#"
+            (() => {
+              const exercise = (frame, method, name) => {
+                const childWindow = frame.contentWindow;
+                const childDocument = frame.contentDocument;
+                const registry = childWindow.customElements;
+                let constructorCount = 0;
+                let errorName = null;
+                childWindow.addEventListener("error", event => {
+                  errorName = event.error && event.error.name;
+                  event.preventDefault();
+                }, { once: true });
+                class DefinedElement extends childWindow.HTMLElement {
+                  constructor() {
+                    super();
+                    constructorCount++;
+                  }
+                }
+                registry.define(name, DefinedElement);
+                const definitionBeforeWrite = registry.get(name) === DefinedElement;
+
+                childDocument[method](`<${name}></${name}>`);
+                const element = childDocument.querySelector(name);
+                return {
+                  registryPreserved: childWindow.customElements === registry,
+                  definitionBeforeWrite,
+                  definitionAfterWrite: registry.get(name) === DefinedElement,
+                  constructorCount,
+                  errorName,
+                  htmlElement: element instanceof childWindow.HTMLElement,
+                  customElement: element instanceof DefinedElement,
+                  ownerDocument: element.ownerDocument === childDocument
+                };
+              };
+
+              const [writeFrame, writelnFrame] = window.__writeCustomElementFrames;
+              return JSON.stringify({
+                write: exercise(writeFrame, "write", "write-defined-element"),
+                writeln: exercise(writelnFrame, "writeln", "writeln-defined-element")
+              });
+            })()
+            "#,
+        )
+        .expect("child document.write predefined custom element result should evaluate");
+
+    assert_eq!(
+        result,
+        r#"{"write":{"registryPreserved":true,"definitionBeforeWrite":true,"definitionAfterWrite":true,"constructorCount":1,"errorName":null,"htmlElement":true,"customElement":true,"ownerDocument":true},"writeln":{"registryPreserved":true,"definitionBeforeWrite":true,"definitionAfterWrite":true,"constructorCount":1,"errorName":null,"htmlElement":true,"customElement":true,"ownerDocument":true}}"#
+    );
+}