Bug 1803984 - Part 1: Don't use the preloaded module request if there's an import map. r=jonco

Differential Revision: https://phabricator.services.mozilla.com/D178298

dom/script/ScriptLoader.cpp

@@ -983,6 +983,17 @@ bool ScriptLoader::ProcessExternalScript(nsIScriptElement* aElement,
     return false;
   }
 
+  // If there are a preloaded request and an import map, we won't use the
+  // preloaded request and will try to create a new one for this, because the
+  // import map isn't preloaded, and the preloaded request may have used the
+  // wrong module specifiers.
+  if (request && request->IsModuleRequest() &&
+      mModuleLoader->HasImportMapRegistered()) {
+    DebugOnly<bool> removed = mModuleLoader->RemoveFetchedModule(request->mURI);
+    MOZ_ASSERT(removed);
+    request = nullptr;
+  }
+
   if (request) {
     // Use the preload request.
 

js/loader/ModuleLoaderBase.cpp

@@ -453,6 +453,11 @@ nsresult ModuleLoaderBase::GetFetchedModuleURLs(nsTArray<nsCString>& aURLs) {
   return NS_OK;
 }
 
+bool ModuleLoaderBase::RemoveFetchedModule(nsIURI* aURL) {
+  MOZ_ASSERT(IsModuleFetched(aURL));
+  return mFetchedModules.Remove(aURL);
+}
+
 void ModuleLoaderBase::SetModuleFetchStarted(ModuleLoadRequest* aRequest) {
   // Update the module map to indicate that a module is currently being fetched.
 

js/loader/ModuleLoaderBase.h

@@ -314,6 +314,8 @@ class ModuleLoaderBase : public nsISupports {
 
   nsresult GetFetchedModuleURLs(nsTArray<nsCString>& aURLs);
 
+  bool RemoveFetchedModule(nsIURI* aURL);
+
   // Internal methods.
 
  private: