fix(streaming): skip control-only SSE blocks with no data

src/openai/_streaming.py

@@ -369,7 +369,7 @@ def decode(self, line: str) -> ServerSentEvent | None:
         # See: https://html.spec.whatwg.org/multipage/server-sent-events.html#event-stream-interpretation  # noqa: E501
 
         if not line:
-            if not self._event and not self._data and not self._last_event_id and self._retry is None:
+            if not self._event and not self._data:
                 return None
 
             sse = ServerSentEvent(

tests/test_streaming.py

@@ -58,6 +58,28 @@ def body() -> Iterator[bytes]:
     await assert_empty_iter(iterator)
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("sync", [True, False], ids=["sync", "async"])
+async def test_control_only_blocks_are_skipped(sync: bool, client: OpenAI, async_client: AsyncOpenAI) -> None:
+    def body() -> Iterator[bytes]:
+        yield b"retry: 1000\n"
+        yield b"\n"
+        yield b"id: 1\n"
+        yield b"\n"
+        yield b'data: {"foo":true}\n'
+        yield b"\n"
+        yield b"\n"
+
+    iterator = make_event_iterator(content=body(), sync=sync, client=client, async_client=async_client)
+
+    sse = await iter_next(iterator)
+    assert sse.id == "1"
+    assert sse.retry == 1000
+    assert sse.json() == {"foo": True}
+
+    await assert_empty_iter(iterator)
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize("sync", [True, False], ids=["sync", "async"])
 async def test_multiple_events(sync: bool, client: OpenAI, async_client: AsyncOpenAI) -> None: