Unexpected LocalProtocolError when making POST request

[basic-bgnr]

Problem statement

I am using httpx (build : 0.28.1) (Edit: HTTP/2, AsyncClient) to make sync GET/POST request to an internal API server. This works fine for single request as it should; but when I try to make several (10+ requests), I get LocalProtocolError which is peculiar.
Edit: Added Traceback

---------------------------------------------------------------------------
LocalProtocolError                        Traceback (most recent call last)
File ~/Desktop/programming/python/.venv/lib/python3.12/site-packages/httpx/_transports/default.py:101, in map_httpcore_exceptions()
    100 try:
--> 101     yield
    102 except Exception as exc:

File ~/Desktop/programming/python/.venv/lib/python3.12/site-packages/httpx/_transports/default.py:250, in HTTPTransport.handle_request(self, request)
    249 with map_httpcore_exceptions():
--> 250     resp = self._pool.handle_request(req)
    252 assert isinstance(resp.stream, typing.Iterable)

File ~/Desktop/programming/python/.venv/lib/python3.12/site-packages/httpcore/_sync/connection_pool.py:216, in ConnectionPool.handle_request(self, request)
    215     self._close_connections(closing)
--> 216     raise exc from None
    218 # Return the response. Note that in this case we still have to manage
    219 # the point at which the response is closed.

File ~/Desktop/programming/python/.venv/lib/python3.12/site-packages/httpcore/_sync/connection_pool.py:196, in ConnectionPool.handle_request(self, request)
    194 try:
    195     # Send the request on the assigned connection.
--> 196     response = connection.handle_request(
    197         pool_request.request
    198     )
    199 except ConnectionNotAvailable:
    200     # In some cases a connection may initially be available to
    201     # handle a request, but then become unavailable.
    202     #
    203     # In this case we clear the connection and try again.

File ~/Desktop/programming/python/.venv/lib/python3.12/site-packages/httpcore/_sync/connection.py:101, in HTTPConnection.handle_request(self, request)
     99     raise exc
--> 101 return self._connection.handle_request(request)

File ~/Desktop/programming/python/.venv/lib/python3.12/site-packages/httpcore/_sync/http2.py:183, in HTTP2Connection.handle_request(self, request)
    181     # If h2 raises a protocol error in some other state then we
    182     # must somehow have made a protocol violation.
--> 183     raise LocalProtocolError(exc)  # pragma: nocover
    185 raise exc

LocalProtocolError: Invalid input ConnectionInputs.RECV_RST_STREAM in state ConnectionState.CLOSED

Seems like the server is returning with HTTP/2 GOAWAY frame; found a open issue on h2 : python-hyper/h2#1181
existing issue with httpx: #2112

Current Workaround:

I catch the exception and make the request again without any changes to the original request (i.e without changing content-length or any other headers), the request completes successfully. Its just the matter of handling exception but I shouldn't be getting any LocalProtocolError

[karpetrosyan]

Please try to provide more context so we can help you, such as the traceback, reproducible code, dependencies, and so on.