LibJS+LibWeb: Another round of bringing module loading closer to spec

In particular, this patch focuses on:
- Updating the old "import assertions" to the new "import attributes"
- Allowing realms as module import referrer

Userland/Libraries/LibWeb/HTML/Scripting/Fetching.cpp

@@ -59,8 +59,8 @@ DeprecatedString module_type_from_module_request(JS::ModuleRequest const& module
     // 1. Let moduleType be "javascript".
     DeprecatedString module_type = "javascript"sv;
 
-    // 2. If moduleRequest.[[Assertions]] has a Record entry such that entry.[[Key]] is "type", then:
-    for (auto const& entry : module_request.assertions) {
+    // 2. If moduleRequest.[[Attributes]] has a Record entry such that entry.[[Key]] is "type", then:
+    for (auto const& entry : module_request.attributes) {
         if (entry.key != "type"sv)
             continue;
 
@@ -719,7 +719,7 @@ void fetch_single_imported_module_script(JS::Realm& realm,
 {
     // 1. Assert: moduleRequest.[[Attributes]] does not contain any Record entry such that entry.[[Key]] is not "type",
     //    because we only asked for "type" attributes in HostGetSupportedImportAttributes.
-    for (auto const& entry : module_request.assertions)
+    for (auto const& entry : module_request.attributes)
         VERIFY(entry.key == "type"sv);
 
     // 2. Let moduleType be the result of running the module type from module request steps given moduleRequest.

Userland/Libraries/LibWeb/HTML/Scripting/ModuleScript.cpp

@@ -68,17 +68,27 @@ WebIDL::ExceptionOr<JS::GCPtr<JavaScriptModuleScript>> JavaScriptModuleScript::c
         return script;
     }
 
-    // 10. For each ModuleRequest record requested of result.[[RequestedModules]]:
+    // 9. For each ModuleRequest record requested of result.[[RequestedModules]]:
     for (auto const& requested : result.value()->requested_modules()) {
         // FIXME: Clarify if this should be checked for all requested before running the steps below.
-        // 9. Assert: requested.[[Assertions]] does not contain any Record entry such that entry.[[Key]] is not "type",
-        //            because we only asked for "type" assertions in HostGetSupportedImportAssertions.
-        VERIFY(all_of(requested.assertions, [](auto const& assertion) { return assertion.key == "type"sv; }));
+        // 1. If requested.[[Attributes]] contains a Record entry such that entry.[[Key]] is not "type", then:
+        for (auto const& attribute : requested.attributes) {
+            if (attribute.key != "type"sv) {
+                // 1. Let error be a new SyntaxError exception.
+                auto error = JS::SyntaxError::create(settings_object.realm(), "Module request attributes must only contain a type attribute"_fly_string);
 
-        // 1. Let url be the result of resolving a module specifier given script and requested.[[Specifier]], catching any exceptions.
+                // 2. Set script's parse error to error.
+                script->set_parse_error(error);
+
+                // 3. Return script.
+                return script;
+            }
+        }
+
+        // 2. Let url be the result of resolving a module specifier given script and requested.[[Specifier]], catching any exceptions.
         auto url = resolve_module_specifier(*script, requested.module_specifier);
 
-        // 2. If the previous step threw an exception, then:
+        // 3. If the previous step threw an exception, then:
         if (url.is_exception()) {
             // FIXME: 1. Set script's parse error to that exception.
 
@@ -86,10 +96,10 @@ WebIDL::ExceptionOr<JS::GCPtr<JavaScriptModuleScript>> JavaScriptModuleScript::c
             return script;
         }
 
-        // 3. Let moduleType be the result of running the module type from module request steps given requested.
+        // 4. Let moduleType be the result of running the module type from module request steps given requested.
         auto module_type = module_type_from_module_request(requested);
 
-        // 4. If the result of running the module type allowed steps given moduleType and settings is false, then:
+        // 5. If the result of running the module type allowed steps given moduleType and settings is false, then:
         if (!settings_object.module_type_allowed(module_type)) {
             // FIXME: 1. Let error be a new TypeError exception.
 
@@ -100,10 +110,10 @@ WebIDL::ExceptionOr<JS::GCPtr<JavaScriptModuleScript>> JavaScriptModuleScript::c
         }
     }
 
-    // 11. Set script's record to result.
+    // 10. Set script's record to result.
     script->m_record = result.value();
 
-    // 12. Return script.
+    // 11. Return script.
     return script;
 }