fix(domparser): preserve HTML parse modes

moli-benchmark/wpt-cross-current/failed-cases.txt

@@ -2553,7 +2553,6 @@ dom/ranges/tentative/OpaqueRange-range-updates.html
 dom/ranges/tentative/OpaqueRange-supported-elements.html
 dom/ranges/tentative/OpaqueRange-unsupported-elements.html
 dom/ranges/tentative/OpaqueRange-validation.html
-domparsing/DOMParser-parseFromString-html.html
 domparsing/DOMParser-parseFromString-url-base-pushstate.html
 domparsing/DOMParser-parseFromString-url-base.html
 domparsing/DOMParser-parseFromString-url-moretests.html

moli-benchmark/wpt-cross-current/passed-cases.txt

@@ -4097,6 +4097,7 @@ dom/traversal/TreeWalker.html
 dom/window-extends-event-target.html
 dom/xpath-result-single-node-value-nullable.html
 domparsing/DOMParser-parseFromString-encoding.html
+domparsing/DOMParser-parseFromString-html.html
 domparsing/DOMParser-parseFromString-stylesheets.html
 domparsing/DOMParser-parseFromString-xml-parsererror.html
 domparsing/createContextualFragment-in-detached-xml-document-crash.html

moli-dom/src/native/host/document.rs

@@ -1120,6 +1120,25 @@ impl DomHost {
         true
     }
 
+    pub fn set_document_quirks_mode_for_handle(
+        &mut self,
+        document_handle: DomHandle,
+        quirks_mode: selectors::matching::QuirksMode,
+    ) -> bool {
+        let Some(document) = self
+            .node_mut(document_handle)
+            .and_then(|node| node.data_mut().as_document_mut())
+        else {
+            return false;
+        };
+        if document.quirks_mode() == quirks_mode {
+            return false;
+        }
+        document.set_quirks_mode(quirks_mode);
+        self.record_mutation(MutationScope::QueryState);
+        true
+    }
+
     pub fn set_document_default_language_for_handle(
         &mut self,
         document_handle: DomHandle,

moli-renderer-v8/src/native_bridge/document/detached_objects/builders/documents.rs

@@ -200,16 +200,34 @@ pub(crate) fn build_detached_document_object_from_dom_host_with_content_type<'s>
     character_set: Option<&str>,
 ) -> Option<v8::Local<'s, v8::Object>> {
     let url = detached_document_url(&parsed);
+    let quirks_mode = parsed.dom().document()?.quirks_mode();
+    let compat_mode = if quirks_mode == selectors::matching::QuirksMode::Quirks {
+        "BackCompat"
+    } else {
+        "CSS1Compat"
+    };
     let content_type = content_type.unwrap_or(parsed.dom().document()?.content_type());
     let document = new_detached_document_shell(scope, kind, content_type, url)?;
-    if let Some(state) = detached_state_object(scope, document)
-        && let Some(character_set) = character_set
-    {
+    if let Some(state) = detached_state_object(scope, document) {
         let _ = state.set(
             scope,
-            v8str(scope, "characterSet").into(),
-            v8_string(scope, character_set)?.into(),
+            v8str(scope, "compatMode").into(),
+            v8_string(scope, compat_mode)?.into(),
         );
+        if let Some(character_set) = character_set {
+            let _ = state.set(
+                scope,
+                v8str(scope, "characterSet").into(),
+                v8_string(scope, character_set)?.into(),
+            );
+        }
+    }
+    if let Some(document_handle) = detached_native_handle(scope, document)
+        && let Some(runtime_ptr) = context_host_ptr_from_global_bridge(scope)
+    {
+        let _ = unsafe { &mut *runtime_ptr }
+            .dom_host_mut()
+            .set_document_quirks_mode_for_handle(document_handle, quirks_mode);
     }
     import_detached_document_children_from_host(scope, document, &parsed)?;
     Some(document)

moli-renderer-v8/src/native_bridge/document/detached_surface/document_state.rs

@@ -267,10 +267,14 @@ pub(in crate::native_bridge) fn bridge_detached_document_character_set_callback<
 
 pub(in crate::native_bridge) fn bridge_detached_document_compat_mode_callback<'a>(
     scope: &mut v8::PinScope<'a, '_>,
-    _args: v8::FunctionCallbackArguments<'a>,
+    args: v8::FunctionCallbackArguments<'a>,
     mut rv: v8::ReturnValue<'_, v8::Value>,
 ) {
-    set_string_return_value(scope, &mut rv, "CSS1Compat");
+    let compat_mode = v8::Local::<v8::Object>::try_from(args.get(0))
+        .ok()
+        .map(|document| detached_document_state_string(scope, document, "compatMode", "CSS1Compat"))
+        .unwrap_or_else(|| "CSS1Compat".to_owned());
+    set_string_return_value(scope, &mut rv, &compat_mode);
 }
 
 pub(in crate::native_bridge) fn bridge_detached_document_referrer_callback<'a>(

moli-renderer-v8/src/script_vm/tests/dom_elements/detached/detached_document_and_element_surfaces.rs

@@ -271,6 +271,44 @@ fn adopted_xml_cdata_uses_html_fragment_serialization() {
     );
 }
 
+#[test]
+fn domparser_html_preserves_quirks_mode_and_parses_with_scripting_disabled() {
+    let mut vm = new_storage_test_vm("https://domparser-html-mode.test/");
+
+    let result = vm
+        .eval(
+            r#"
+(() => {
+  const parser = new DOMParser();
+  const quirks = parser.parseFromString(
+    "<html><head></head><body></body></html>",
+    "text/html"
+  );
+  const standards = parser.parseFromString(
+    "<!doctype html><html><head></head><body></body></html>",
+    "text/html"
+  );
+  const noscript = parser.parseFromString(
+    "<body><noscript><p id='first'></p><p id='second'></p></noscript></body>",
+    "text/html"
+  );
+  return JSON.stringify({
+    quirks: quirks.compatMode,
+    standards: standards.compatMode,
+    noscriptChildren: Array.from(noscript.querySelector("noscript").children)
+      .map(element => element.id)
+  });
+})()
+"#,
+        )
+        .expect("DOMParser HTML parse mode probe should evaluate");
+
+    assert_eq!(
+        result,
+        r#"{"quirks":"BackCompat","standards":"CSS1Compat","noscriptChildren":["first","second"]}"#
+    );
+}
+
 #[test]
 fn detached_query_brand_checks_accept_standard_prototype_methods() {
     let mut vm = new_storage_test_vm("https://detached-query-brand-check.test/");