Add check for h2.connection.ConnectionState.CLOSED in AsyncHTTP2Connection.is_available (#679)

* Add check for `h2.connection.ConnectionState.CLOSED` in `AsyncHTTP2Connection.is_available`

* Add sync implementation

* Add test for closed connection

* Regenerate sync tests with `unasync`

* Use async with

* Add anyio annotation

---------

Co-authored-by: Tom Christie <[email protected]>

Author: zanieb

Diff for: httpcore/_async/http2.py

@@ -433,6 +433,10 @@ def is_available(self) -> bool:
             self._state != HTTPConnectionState.CLOSED
             and not self._connection_error
             and not self._used_all_stream_ids
+            and not (
+                self._h2_state.state_machine.state
+                == h2.connection.ConnectionState.CLOSED
+            )
         )
 
     def has_expired(self) -> bool:

Diff for: httpcore/_sync/http2.py

@@ -433,6 +433,10 @@ def is_available(self) -> bool:
             self._state != HTTPConnectionState.CLOSED
             and not self._connection_error
             and not self._used_all_stream_ids
+            and not (
+                self._h2_state.state_machine.state
+                == h2.connection.ConnectionState.CLOSED
+            )
         )
 
     def has_expired(self) -> bool:

Diff for: tests/_async/test_http2.py

@@ -52,6 +52,40 @@ async def test_http2_connection():
         )
 
 
+@pytest.mark.anyio
+async def test_http2_connection_closed():
+    origin = Origin(b"https", b"example.com", 443)
+    stream = AsyncMockStream(
+        [
+            hyperframe.frame.SettingsFrame().serialize(),
+            hyperframe.frame.HeadersFrame(
+                stream_id=1,
+                data=hpack.Encoder().encode(
+                    [
+                        (b":status", b"200"),
+                        (b"content-type", b"plain/text"),
+                    ]
+                ),
+                flags=["END_HEADERS"],
+            ).serialize(),
+            hyperframe.frame.DataFrame(
+                stream_id=1, data=b"Hello, world!", flags=["END_STREAM"]
+            ).serialize(),
+            # Connection is closed after the first response
+            hyperframe.frame.GoAwayFrame(stream_id=0, error_code=0).serialize(),
+        ]
+    )
+    async with AsyncHTTP2Connection(
+        origin=origin, stream=stream, keepalive_expiry=5.0
+    ) as conn:
+        await conn.request("GET", "https://example.com/")
+
+        with pytest.raises(RemoteProtocolError):
+            await conn.request("GET", "https://example.com/")
+
+        assert not conn.is_available()
+
+
 @pytest.mark.anyio
 async def test_http2_connection_post_request():
     origin = Origin(b"https", b"example.com", 443)

Diff for: tests/_sync/test_http2.py

@@ -53,6 +53,40 @@ def test_http2_connection():
 
 
 
+def test_http2_connection_closed():
+    origin = Origin(b"https", b"example.com", 443)
+    stream = MockStream(
+        [
+            hyperframe.frame.SettingsFrame().serialize(),
+            hyperframe.frame.HeadersFrame(
+                stream_id=1,
+                data=hpack.Encoder().encode(
+                    [
+                        (b":status", b"200"),
+                        (b"content-type", b"plain/text"),
+                    ]
+                ),
+                flags=["END_HEADERS"],
+            ).serialize(),
+            hyperframe.frame.DataFrame(
+                stream_id=1, data=b"Hello, world!", flags=["END_STREAM"]
+            ).serialize(),
+            # Connection is closed after the first response
+            hyperframe.frame.GoAwayFrame(stream_id=0, error_code=0).serialize(),
+        ]
+    )
+    with HTTP2Connection(
+        origin=origin, stream=stream, keepalive_expiry=5.0
+    ) as conn:
+        conn.request("GET", "https://example.com/")
+
+        with pytest.raises(RemoteProtocolError):
+            conn.request("GET", "https://example.com/")
+
+        assert not conn.is_available()
+
+
+
 def test_http2_connection_post_request():
     origin = Origin(b"https", b"example.com", 443)
     stream = MockStream(