Http2 protocol violation about h2

[erebe]

Hello @LucioFranco
Most likely yes, I haven't tried with a python client, but the issue you describe is the one I had with nginx.
Only RST_STREAM(NO_ERROR) is allowed on early server response.

I was planning to open an issue in tonic to ask to bump h2 version, once a new release is made, but seems you are ahead of me

[seanmonstar]

Thanks again for the excellent work! If you're ever interested in helping on other aspects of h2, we'd welcome your work gladly! <3

[seanmonstar]

Yes, I believe we've discussed before that there are cases that this should send NO_ERROR instead of CANCEL. Probably only in this specific case:

The full response has been sent (or scheduled to send), and any option DATA and trailers. Basically, that an end-of-stream frame is going out.

I think CANCEL is still correct in the general case, where the user has dropped all handles but never triggered end-of-stream, and also if the client drops handle waiting for the response.

[erebe]

Hello, thanks for the answer !

So I am at the right place 🎆
Is changing the maybe_cancel code by something like this would feel right to you ?
Or is there some other cases to handle ?

fn maybe_cancel(stream: &mut store::Ptr, actions: &mut Actions, counts: &mut Counts) {
    if stream.is_canceled_interest() {
+        // To match HalfClosedLocal(Streaming) state
+       let reason = if stream.state.is_send_closed() && stream.state.is_recv_streaming() {
+            Reason::NO_ERROR
+        } else {
+           Reason::CANCEL
+        };

        actions
            .send
            .schedule_implicit_reset(stream, reason, counts, &mut actions.task);
        actions.recv.enqueue_reset_expiration(stream, counts);
    }
}

[seanmonstar]

Ummmm, hard for me to remember. I imagine if you changed that function without the conditional, some unit test would complain? That might show which unit test needs to be updated, or maybe we dont have this specific case as a test...

[erebe]

Ok, so I am impressed by the quality of your tests ...
Would dream to have those mock in my projects.

Regarding the issue, by adding an is_server() check in the condition and adapting 1 test that seems to match my case.
Everything is green with a cargo test --all-features --all

diff --git a/src/proto/streams/streams.rs b/src/proto/streams/streams.rs
index f11ee08..bfce840 100644
--- a/src/proto/streams/streams.rs
+++ b/src/proto/streams/streams.rs
@@ -1461,9 +1461,16 @@ fn drop_stream_ref(inner: &Mutex<Inner>, key: store::Key) {

 fn maybe_cancel(stream: &mut store::Ptr, actions: &mut Actions, counts: &mut Counts) {
     if stream.is_canceled_interest() {
+        // To match HalfClosedLocal(Streaming) state
+        let reason = if counts.peer().is_server() && stream.state.is_send_closed() && stream.state.is_recv_streaming() {
+            Reason::NO_ERROR
+        } else {
+            Reason::CANCEL
+        };
+
         actions
             .send
-            .schedule_implicit_reset(stream, Reason::CANCEL, counts, &mut actions.task);
+            .schedule_implicit_reset(stream, reason, counts, &mut actions.task);
         actions.recv.enqueue_reset_expiration(stream, counts);
     }
 }
diff --git a/tests/h2-tests/tests/server.rs b/tests/h2-tests/tests/server.rs
index b3bf1a2..e61fd3b 100644
--- a/tests/h2-tests/tests/server.rs
+++ b/tests/h2-tests/tests/server.rs
@@ -566,7 +566,7 @@ async fn sends_reset_cancel_when_req_body_is_dropped() {
         client
             .recv_frame(frames::headers(1).response(200).eos())
             .await;
-        client.recv_frame(frames::reset(1).cancel()).await;
+        client.recv_frame(frames::reset(1).reason(Reason::NO_ERROR)).await;
     };

     let srv = async move {

If this seems good to you, I can go forward and make a PR next week.
If you require some other things before, let me know

[seanmonstar]

Nice, looks good to me!

[erebe]

Here we are #634 :)
It needs some approval to run the github actions

[erebe]

Thank you for the kind words and your reactivity ^^

By any chances, do you plan to make a new release soonish ?

[LucioFranco]

This feels related to hyperium/tonic#992, right?

[erebe]

Thank you @seanmonstar and @LucioFranco , I am closing the issue as it is resolved and released 👍