Default Python workers to protocol 1.20

.github/workflows/ci.yml

@@ -159,7 +159,6 @@ jobs:
     timeout-minutes: 25
     needs: [lint, test]
     env:
-      DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION: ${{ inputs.cooperative_qualification && '1.20' || '1.19' }}
       DURABLE_WORKFLOW_COOPERATIVE_QUALIFICATION: ${{ inputs.cooperative_qualification && '1' || '0' }}
       DURABLE_WORKFLOW_NATIVE_SOURCE: ${{ github.workspace }}/native
       COMPOSE_FILE: docker-compose.test.yml

README.md

@@ -115,12 +115,15 @@ capabilities with Server at startup. Use stable `2.x` SDK and Server channels
 for new applications. The [compatibility guide](https://durable-workflow.com/docs/2.0/compatibility/)
 documents protocol and upgrade guarantees.
 
-## Cooperative cancellation release candidate
+## Worker protocol and cooperative cancellation
+
+Workers use protocol 1.20 by default. For a Server that supports only 1.19, set
+`DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION=1.19`. This changes the request protocol
+without enabling optional worker features.
 
 Use `request_cancellation()` for bounded, replayable workflow cleanup. Opt in
 against a Server that advertises protocol 1.20 and the required capabilities:
-set `DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION=1.20` and include
-`cooperative_cancellation` in the Worker's `capabilities`. Durable local callback
+include `cooperative_cancellation` in the Worker's `capabilities`. Durable local callback
 admission also needs `prepared_local_activities`, with
 `prepared_local_activity_cancellation_policies` for explicit local policies.
 Independently cancellable scopes remain disabled.
@@ -156,11 +159,10 @@ to true. CI verifies that checkout, builds the candidate Server, enables protoco
 authority and exact source provenance. An optional exact `native_commit` mounts
 that public Native checkout read-only into the test stack. The image's published
 Composer authority stays intact and the evidence identifies the source overlay.
-These are source qualification runs. For a local
-candidate, set `DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION=1.20` before starting
-Compose and `DURABLE_WORKFLOW_COOPERATIVE_QUALIFICATION=1` for pytest. These cases
-fail if the runtime does not discover the required capability. Ordinary CI
-keeps protocol 1.19 and skips this unpublished feature's connected cases.
+These are source qualification runs. For a local candidate, set
+`DURABLE_WORKFLOW_COOPERATIVE_QUALIFICATION=1` for pytest. These cases fail if the
+runtime does not discover the required capability. Ordinary CI uses the SDK's
+default protocol and skips the optional connected cooperative cases.
 
 ## License
 

docker-compose.test.yml

@@ -30,8 +30,8 @@ services:
       WORKFLOW_SERVER_AUTH_DRIVER: token
       WORKFLOW_SERVER_AUTH_TOKEN: "test-token"
       DW_WORKFLOW_TASK_TIMEOUT: 10
-      # Candidate cooperative qualification is explicit. Published defaults remain 1.19.
-      DW_WORKER_PROTOCOL_VERSION: "${DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION:-1.19}"
+      # Optional cooperative qualification remains explicit.
+      DW_WORKER_PROTOCOL_VERSION: "${DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION:-1.20}"
     depends_on:
       mysql:
         condition: service_healthy

docs/cooperative-cancellation-design.md

@@ -1,8 +1,8 @@
 # Cooperative cancellation source design
 
 This describes the unfinished source candidate for shared cancellation issue 136.
-The default worker protocol remains 1.19. Cooperation requires explicit protocol
-1.20 opt-in and a compatible Server and Native backend. The shared specification
+The default worker protocol is 1.20. Cooperation requires an explicit worker
+capability opt-in and a compatible Server and Native backend. The shared specification
 and published mixed-language qualification remain pending.
 
 ## Recorded context

pyproject.toml

@@ -74,7 +74,7 @@ durable-workflow-workflow-updates-conformance = "durable_workflow.workflow_updat
 product-train = "2.6.0-rc.2"
 registry-version = "2.6.0rc2"
 supported-server-versions = "2.5.16"
-worker-protocol-version = "1.19"
+worker-protocol-version = "1.20"
 control-plane-version = "2"
 durable-selection = true
 durable-selection-minimum-worker-protocol-version = "1.19"

src/durable_workflow/client.py

@@ -72,7 +72,8 @@
 from .retry_policy import TransportRetryPolicy
 from .worker_session import WorkerSessionOptions
 
-PROTOCOL_VERSION = "1.19"
+PROTOCOL_VERSION = "1.20"
+MINIMUM_WORKER_PROTOCOL_VERSION = "1.19"
 CONTROL_PLANE_VERSION = "2"
 PORTABLE_WORKER_AFFINITY_CAPABILITY_MANIFEST: dict[str, dict[str, str | bool]] = {
     "local_activities": {

src/durable_workflow/worker.py

@@ -55,6 +55,7 @@
     CONTROL_PLANE_REQUEST_CONTRACT_VERSION,
     CONTROL_PLANE_VERSION,
     DEFAULT_SDK_VERSION,
+    MINIMUM_WORKER_PROTOCOL_VERSION,
     PORTABLE_WORKER_AFFINITY_CAPABILITY_MANIFEST,
     PROTOCOL_VERSION,
     Client,
@@ -874,6 +875,16 @@ def _server_protocol_compatible(server_version: str, sdk_version: str) -> bool:
 
 
 def _validate_server_compatibility(info: dict[str, Any]) -> None:
+    requested_protocol = _protocol_version_from_env(
+        "DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", PROTOCOL_VERSION,
+    )
+    if requested_protocol not in (MINIMUM_WORKER_PROTOCOL_VERSION, PROTOCOL_VERSION):
+        raise RuntimeError(
+            "Server compatibility error: sdk-python supports worker protocol "
+            f"{MINIMUM_WORKER_PROTOCOL_VERSION} or protocol {PROTOCOL_VERSION}; "
+            f"requested {requested_protocol!r}."
+        )
+
     control_plane = info.get("control_plane")
     if not isinstance(control_plane, dict):
         raise RuntimeError(
@@ -911,15 +922,15 @@ def _validate_server_compatibility(info: dict[str, Any]) -> None:
     if not isinstance(worker_protocol, dict):
         raise RuntimeError(
             "Server compatibility error: missing worker_protocol manifest; "
-            f"sdk-python requires worker_protocol.version {PROTOCOL_VERSION}."
+            f"sdk-python requires worker_protocol.version {requested_protocol}."
         )
 
     worker_protocol_version = _manifest_version(worker_protocol)
-    if not _server_protocol_compatible(worker_protocol_version, PROTOCOL_VERSION):
+    if not _server_protocol_compatible(worker_protocol_version, requested_protocol):
         raise RuntimeError(
             "Server compatibility error: incompatible worker_protocol.version "
             f"{worker_protocol_version!r}; sdk-python requires major-equal and "
-            f"minor>={PROTOCOL_VERSION!r}."
+            f"minor>={requested_protocol!r}."
         )
 
     auth_composition = info.get("auth_composition_contract")

tests/test_cancellation_scope_opening.py

@@ -152,8 +152,8 @@ async def test_invalid_authority_fails_before_io(change: dict[str, Any]) -> None
             send.assert_not_awaited()
 
 
-async def test_published_protocol_refuses_opening_before_io(monkeypatch: pytest.MonkeyPatch) -> None:
-    monkeypatch.delenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION")
+async def test_previous_protocol_refuses_opening_before_io(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "1.19")
     async with Client("http://server", namespace="tenant") as client:
         with patch.object(client, "_request", new_callable=AsyncMock) as send:
             with pytest.raises(ValueError, match="1.20"):

tests/test_client.py

@@ -164,10 +164,15 @@ def test_control_plane_headers(self, client: Client) -> None:
 
     def test_worker_headers(self, client: Client) -> None:
         h = client._headers(worker=True)
-        assert PROTOCOL_VERSION == "1.19"
+        assert PROTOCOL_VERSION == "1.20"
         assert h["X-Durable-Workflow-Protocol-Version"] == PROTOCOL_VERSION
         assert "X-Durable-Workflow-Control-Plane-Version" not in h
 
+    def test_explicit_previous_worker_protocol(self, client: Client, monkeypatch: pytest.MonkeyPatch) -> None:
+        monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "1.19")
+        assert client._headers(worker=True)["X-Durable-Workflow-Protocol-Version"] == "1.19"
+        assert client._headers(worker=False)["X-Durable-Workflow-Control-Plane-Version"] == "2"
+
     def test_conformance_protocol_header_overrides(self, client: Client, monkeypatch: pytest.MonkeyPatch) -> None:
         monkeypatch.setenv("DURABLE_WORKFLOW_CONTROL_PLANE_VERSION", "3")
         monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "2.0")

tests/test_cooperative_cancellation_client.py

@@ -406,14 +406,11 @@ async def test_activity_stop_receipt_rejects_invalid_identity_before_io(
 
 
 @pytest.mark.asyncio
-@pytest.mark.parametrize("version", [None, "1.19", "2.20", "invalid"])
-async def test_activity_stop_receipt_requires_explicit_worker_opt_in(
-    client: Client, monkeypatch: pytest.MonkeyPatch, version: str | None,
+@pytest.mark.parametrize("version", ["1.19", "2.20", "invalid"])
+async def test_activity_stop_receipt_requires_compatible_protocol(
+    client: Client, monkeypatch: pytest.MonkeyPatch, version: str,
 ) -> None:
-    if version is None:
-        monkeypatch.delenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", raising=False)
-    else:
-        monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", version)
+    monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", version)
     with patch.object(client._http, "request", new_callable=AsyncMock) as send, pytest.raises(ValueError):
         await client.acknowledge_activity_cancellation(
             task_id="task/1", activity_attempt_id="attempt-1", lease_owner="worker-1", request_id="original-request",

tests/test_cooperative_cancellation_worker.py

@@ -134,7 +134,7 @@ async def complete(self, **kwargs: Any) -> dict[str, Any]:
         return {"outcome": "completed"}
 
     async def worker(self, monkeypatch: pytest.MonkeyPatch, **kwargs: Any) -> Worker:
-        monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "1.20")
+        monkeypatch.delenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", raising=False)
         # These transport/replay fixtures use local callbacks that share mock
         # state with this process. They never poll or advertise remote handlers.
         local_callbacks = kwargs.pop("activities", [])

tests/test_cooperative_remote_worker.py

@@ -94,7 +94,7 @@ async def application_failure(kind: str) -> None:
 
 @pytest_asyncio.fixture
 async def owner(monkeypatch: pytest.MonkeyPatch):  # type: ignore[no-untyped-def]
-    monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "1.20")
+    monkeypatch.delenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", raising=False)
     client = AsyncMock(spec=Client)
     client.get_cluster_info.return_value = compatible_cluster_info(worker_protocol={
         "version": "1.20", "server_capabilities": {"cooperative_cancellation": True},
@@ -317,8 +317,8 @@ async def test_client_observation_keeps_worker_credentials_namespace_and_fence(m
         assert send.await_args.kwargs["json"] == {"activity_attempt_id": "attempt", "lease_owner": "owner"}
 
 
-async def test_client_observation_requires_explicit_protocol_before_io(monkeypatch: pytest.MonkeyPatch) -> None:
-    monkeypatch.delenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", raising=False)
+async def test_client_observation_refuses_previous_protocol_before_io(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "1.19")
     async with Client("http://runtime.test") as client:
         with (patch.object(client._http, "request", new_callable=AsyncMock) as send,
               pytest.raises(ValueError, match="1.20")):

tests/test_prepared_local_activity_client.py

@@ -66,8 +66,8 @@ async def test_invalid_claim_or_authority_never_starts_transport(change: dict[st
             send.assert_not_awaited()
 
 
-async def test_default_protocol_refuses_before_io(monkeypatch: pytest.MonkeyPatch) -> None:
-    monkeypatch.delenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION")
+async def test_previous_protocol_refuses_before_io(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "1.19")
     async with Client("http://server") as client:
         with patch.object(client, "_request", new_callable=AsyncMock) as send:
             with pytest.raises(ValueError, match="1.20"):

tests/test_release_metadata.py

@@ -45,13 +45,13 @@ def test_worker_release_identity_matches_supported_server_and_protocol() -> None
     assert release["product-train"] == project["version"]
     assert release["registry-version"] == project["version"].replace("-rc.", "rc")
     assert check_release_metadata.VERSION_PATTERN.fullmatch(release["supported-server-versions"]) is not None
-    assert release["worker-protocol-version"] == PROTOCOL_VERSION == "1.19"
+    assert release["worker-protocol-version"] == PROTOCOL_VERSION == "1.20"
     assert release["durable-selection"] is True
     assert release["durable-selection-minimum-worker-protocol-version"] == "1.19"
 
     assert declared_runtime_protocol_version(
         (REPO_ROOT / "src" / "durable_workflow" / "client.py").read_text(encoding="utf-8")
-    ) == "1.19"
+    ) == "1.20"
 
 
 def pypi_json(source: SourceMetadata, **overrides: object) -> bytes:

tests/test_worker.py

@@ -1113,6 +1113,39 @@ async def test_register_rejects_worker_protocol_major_mismatch(self, mock_client
             await worker._register()
         mock_client.register_worker.assert_not_called()
 
+    @pytest.mark.asyncio
+    async def test_register_accepts_explicit_previous_protocol(
+        self, mock_client: AsyncMock, monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", "1.19")
+        mock_client.get_cluster_info = AsyncMock(
+            return_value=compatible_cluster_info(worker_protocol={"version": "1.19"})
+        )
+        worker = Worker(mock_client, task_queue="q1", workflows=[TestWorkflow], activities=[])
+        await worker._register()
+        mock_client.register_worker.assert_called_once()
+
+    @pytest.mark.asyncio
+    async def test_default_protocol_refuses_previous_server_before_registration(self, mock_client: AsyncMock) -> None:
+        mock_client.get_cluster_info = AsyncMock(
+            return_value=compatible_cluster_info(worker_protocol={"version": "1.19"})
+        )
+        worker = Worker(mock_client, task_queue="q1", workflows=[TestWorkflow], activities=[])
+        with pytest.raises(RuntimeError, match="minor>='1.20'"):
+            await worker._register()
+        mock_client.register_worker.assert_not_called()
+
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize("version", ["1.18", "1.21", "2.0"])
+    async def test_register_rejects_unsupported_protocol_override(
+        self, mock_client: AsyncMock, monkeypatch: pytest.MonkeyPatch, version: str,
+    ) -> None:
+        monkeypatch.setenv("DURABLE_WORKFLOW_WORKER_PROTOCOL_VERSION", version)
+        worker = Worker(mock_client, task_queue="q1", workflows=[TestWorkflow], activities=[])
+        with pytest.raises(RuntimeError, match="supports worker protocol 1.19 or protocol 1.20"):
+            await worker._register()
+        mock_client.register_worker.assert_not_called()
+
     @pytest.mark.asyncio
     async def test_register_accepts_higher_compatible_minor_protocol(self, mock_client: AsyncMock) -> None:
         # Server is one minor ahead of the SDK. MINOR bumps in workflow:v2's