Bug 1835886 - Cancel outstanding load requests when a document is detached from a global r=smaug

Also cancel module load requests when cancelling requests generally.

What was happening here was that a previous load was completing and calling
into the wrong module loader, because the loader to use is determined via the
current global, and this was now associated with a different document / script
loader / module loader.

Differential Revision: https://phabricator.services.mozilla.com/D179787

Author: jonco3

dom/script/ScriptLoader.cpp

@@ -258,19 +258,21 @@ ScriptLoader::~ScriptLoader() {
 void ScriptLoader::SetGlobalObject(nsIGlobalObject* aGlobalObject) {
   if (!aGlobalObject) {
     // The document is being detached.
+    CancelAndClearScriptLoadRequests();
     return;
   }
 
   MOZ_ASSERT(!HasPendingRequests());
 
-  if (mModuleLoader) {
-    MOZ_ASSERT(mModuleLoader->GetGlobalObject() == aGlobalObject);
-    return;
+  if (!mModuleLoader) {
+    // The module loader is associated with a global object, so don't create it
+    // until we have a global set.
+    mModuleLoader = new ModuleLoader(this, aGlobalObject, ModuleLoader::Normal);
   }
 
-  // The module loader is associated with a global object, so don't create it
-  // until we have a global set.
-  mModuleLoader = new ModuleLoader(this, aGlobalObject, ModuleLoader::Normal);
+  MOZ_ASSERT(mModuleLoader->GetGlobalObject() == aGlobalObject);
+  MOZ_ASSERT(aGlobalObject->GetModuleLoader(dom::danger::GetJSContext()) ==
+             mModuleLoader);
 }
 
 void ScriptLoader::RegisterContentScriptModuleLoader(ModuleLoader* aLoader) {
@@ -1428,6 +1430,10 @@ void ScriptLoader::CancelAndClearScriptLoadRequests() {
   mXSLTRequests.CancelRequestsAndClear();
   mOffThreadCompilingRequests.CancelRequestsAndClear();
 
+  if (mModuleLoader) {
+    mModuleLoader->CancelAndClearDynamicImports();
+  }
+
   for (ModuleLoader* loader : mWebExtModuleLoaders) {
     loader->CancelAndClearDynamicImports();
   }

js/loader/ModuleLoaderBase.cpp

@@ -934,15 +934,19 @@ void ModuleLoaderBase::FinishDynamicImportAndReject(ModuleLoadRequest* aRequest,
   FinishDynamicImport(jsapi.cx(), aRequest, aResult, nullptr);
 }
 
+/* static */
 void ModuleLoaderBase::FinishDynamicImport(
     JSContext* aCx, ModuleLoadRequest* aRequest, nsresult aResult,
     JS::Handle<JSObject*> aEvaluationPromise) {
+  LOG(("ScriptLoadRequest (%p): Finish dynamic import %x %d", aRequest,
+       unsigned(aResult), JS_IsExceptionPending(aCx)));
+
+  MOZ_ASSERT(GetCurrentModuleLoader(aCx) == aRequest->mLoader);
+
   // If aResult is a failed result, we don't have an EvaluationPromise. If it
   // succeeded, evaluationPromise may still be null, but in this case it will
   // be handled by rejecting the dynamic module import promise in the JSAPI.
   MOZ_ASSERT_IF(NS_FAILED(aResult), !aEvaluationPromise);
-  LOG(("ScriptLoadRequest (%p): Finish dynamic import %x %d", aRequest,
-       unsigned(aResult), JS_IsExceptionPending(aCx)));
 
   // Complete the dynamic import, report failures indicated by aResult or as a
   // pending exception on the context.
@@ -1182,6 +1186,7 @@ nsresult ModuleLoaderBase::EvaluateModuleInContext(
     JSContext* aCx, ModuleLoadRequest* aRequest,
     JS::ModuleErrorBehaviour errorBehaviour) {
   MOZ_ASSERT(aRequest->mLoader == this);
+  MOZ_ASSERT(mGlobalObject->GetModuleLoader(aCx) == this);
 
   AUTO_PROFILER_LABEL("ModuleLoaderBase::EvaluateModule", JS);
 
@@ -1215,6 +1220,7 @@ nsresult ModuleLoaderBase::EvaluateModuleInContext(
 
   JS::Rooted<JSObject*> module(aCx, moduleScript->ModuleRecord());
   MOZ_ASSERT(module);
+  MOZ_ASSERT(CurrentGlobalOrNull(aCx) == GetNonCCWObjectGlobal(module));
 
   if (!xpc::Scriptability::AllowedIfExists(module)) {
     return NS_OK;