3 files changed, 33 insertions, 14 deletions
diff --git a/dom/streams/TransformStream.cpp b/dom/streams/TransformStream.cpp
index e517ecda89..3b78cabeea 100644
--- a/dom/streams/TransformStream.cpp
+++ b/dom/streams/TransformStream.cpp
@@ -20,14 +20,6 @@
 #include "mozilla/dom/TransformerBinding.h"
 #include "nsWrapperCache.h"
 
-// XXX: GCC somehow does not allow attributes before lambda return types, while
-// clang requires so. See also bug 1627007.
-#ifdef __clang__
-#  define MOZ_CAN_RUN_SCRIPT_BOUNDARY_LAMBDA MOZ_CAN_RUN_SCRIPT_BOUNDARY
-#else
-#  define MOZ_CAN_RUN_SCRIPT_BOUNDARY_LAMBDA
-#endif
-
 namespace mozilla::dom {
 
 using namespace streams_abstract;
diff --git a/dom/streams/UnderlyingSinkCallbackHelpers.cpp b/dom/streams/UnderlyingSinkCallbackHelpers.cpp
index 91562a2db3..6277fd26e0 100644
--- a/dom/streams/UnderlyingSinkCallbackHelpers.cpp
+++ b/dom/streams/UnderlyingSinkCallbackHelpers.cpp
@@ -111,6 +111,24 @@ already_AddRefed<Promise> UnderlyingSinkAlgorithms::AbortCallback(
 }
 
 // https://streams.spec.whatwg.org/#writable-set-up
+// This one is not covered by the above section as the spec expects any spec
+// implementation to explicitly return a promise for this callback. It's still
+// useful for Gecko as error handling is very frequently done with
+// ErrorResult instead of a rejected promise. See also
+// https://github.com/whatwg/streams/issues/1253.
+already_AddRefed<Promise> UnderlyingSinkAlgorithmsWrapper::WriteCallback(
+    JSContext* aCx, JS::Handle<JS::Value> aChunk,
+    WritableStreamDefaultController& aController, ErrorResult& aRv) {
+  nsCOMPtr<nsIGlobalObject> global = xpc::CurrentNativeGlobal(aCx);
+  return PromisifyAlgorithm(
+      global,
+      [&](ErrorResult& aRv) {
+        return WriteCallbackImpl(aCx, aChunk, aController, aRv);
+      },
+      aRv);
+}
+
+// https://streams.spec.whatwg.org/#writable-set-up
 // Step 2.1: Let closeAlgorithmWrapper be an algorithm that runs these steps:
 already_AddRefed<Promise> UnderlyingSinkAlgorithmsWrapper::CloseCallback(
     JSContext* aCx, ErrorResult& aRv) {
@@ -182,19 +200,20 @@ WritableStreamToOutput::OnOutputStreamReady(nsIAsyncOutputStream* aStream) {
   return NS_OK;
 }
 
-already_AddRefed<Promise> WritableStreamToOutput::WriteCallback(
+already_AddRefed<Promise> WritableStreamToOutput::WriteCallbackImpl(
     JSContext* aCx, JS::Handle<JS::Value> aChunk,
-    WritableStreamDefaultController& aController, ErrorResult& aError) {
+    WritableStreamDefaultController& aController, ErrorResult& aRv) {
   ArrayBufferViewOrArrayBuffer data;
   if (!data.Init(aCx, aChunk)) {
-    aError.StealExceptionFromJSContext(aCx);
+    aRv.MightThrowJSException();
+    aRv.StealExceptionFromJSContext(aCx);
     return nullptr;
   }
   // buffer/bufferView
   MOZ_ASSERT(data.IsArrayBuffer() || data.IsArrayBufferView());
 
-  RefPtr<Promise> promise = Promise::Create(mParent, aError);
-  if (NS_WARN_IF(aError.Failed())) {
+  RefPtr<Promise> promise = Promise::Create(mParent, aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
     return nullptr;
   }
 
diff --git a/dom/streams/UnderlyingSinkCallbackHelpers.h b/dom/streams/UnderlyingSinkCallbackHelpers.h
index c99c8709ce..0717176aca 100644
--- a/dom/streams/UnderlyingSinkCallbackHelpers.h
+++ b/dom/streams/UnderlyingSinkCallbackHelpers.h
@@ -135,6 +135,10 @@ class UnderlyingSinkAlgorithmsWrapper : public UnderlyingSinkAlgorithmsBase {
     aRetVal.setUndefined();
   }
 
+  MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> WriteCallback(
+      JSContext* aCx, JS::Handle<JS::Value> aChunk,
+      WritableStreamDefaultController& aController, ErrorResult& aRv) final;
+
   MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> CloseCallback(
       JSContext* aCx, ErrorResult& aRv) final;
 
@@ -142,6 +146,10 @@ class UnderlyingSinkAlgorithmsWrapper : public UnderlyingSinkAlgorithmsBase {
       JSContext* aCx, const Optional<JS::Handle<JS::Value>>& aReason,
       ErrorResult& aRv) final;
 
+  virtual already_AddRefed<Promise> WriteCallbackImpl(
+      JSContext* aCx, JS::Handle<JS::Value> aChunk,
+      WritableStreamDefaultController& aController, ErrorResult& aRv) = 0;
+
   virtual already_AddRefed<Promise> CloseCallbackImpl(JSContext* aCx,
                                                       ErrorResult& aRv) {
     // (closeAlgorithm is optional, give null by default)
@@ -169,7 +177,7 @@ class WritableStreamToOutput final : public UnderlyingSinkAlgorithmsWrapper,
 
   // Streams algorithms
 
-  already_AddRefed<Promise> WriteCallback(
+  already_AddRefed<Promise> WriteCallbackImpl(
       JSContext* aCx, JS::Handle<JS::Value> aChunk,
       WritableStreamDefaultController& aController, ErrorResult& aRv) override;