chore: remove Python < 3.9 support (#728) (#730)

* chore: remove Python < 3.9 logic and update dependencies (#728)

- Bump the minimum supported Python version from 3.8 to 3.9
- Remove macOS-specific code for Python < 3.8
- Update references in README, build.py, and poetry.lock accordingly

Closes #728

* rollback poetry.lock file

* fixed code formatting

Author: ozeranskii

README.md

@@ -1373,7 +1373,7 @@ users are encouraged to not use gevent in asyncio applications (including Tempor
 
 # Development
 
-The Python SDK is built to work with Python 3.8 and newer. It is built using
+The Python SDK is built to work with Python 3.9 and newer. It is built using
 [SDK Core](https://github.com/temporalio/sdk-core/) which is written in Rust.
 
 ### Building

build.py

@@ -16,7 +16,7 @@ def build(setup_kwargs):
                 path="temporalio/bridge/Cargo.toml",
                 binding=Binding.PyO3,
                 py_limited_api=True,
-                features=["pyo3/abi3-py38"],
+                features=["pyo3/abi3-py39"],
             )
         ],
         zip_safe=False,

pyproject.toml

@@ -214,7 +214,7 @@ exclude = [
 ]
 
 [tool.ruff]
-target-version = "py38"
+target-version = "py39"
 
 [build-system]
 build-backend = "poetry.core.masonry.api"

tests/conftest.py

@@ -39,12 +39,6 @@
 from temporalio.testing import WorkflowEnvironment
 from tests.helpers.worker import ExternalPythonWorker, ExternalWorker
 
-# Due to https://github.com/python/cpython/issues/77906, multiprocessing on
-# macOS starting with Python 3.8 has changed from "fork" to "spawn". For
-# pre-3.8, we are changing it for them.
-if sys.version_info < (3, 8) and sys.platform.startswith("darwin"):
-    multiprocessing.set_start_method("spawn", True)
-
 
 def pytest_addoption(parser):
     parser.addoption(

tests/worker/test_replayer.py

@@ -171,9 +171,11 @@ async def test_replayer_workflow_nondeterministic(client: Client) -> None:
 
 
 async def test_replayer_workflow_nondeterministic_json() -> None:
-    with Path(__file__).with_name("test_replayer_nondeterministic_history.json").open(
-        "r"
-    ) as f:
+    with (
+        Path(__file__)
+        .with_name("test_replayer_nondeterministic_history.json")
+        .open("r") as f
+    ):
         history_json = f.read()
     with pytest.raises(workflow.NondeterminismError):
         await Replayer(workflows=[SayHelloWorkflow]).replay_workflow(
@@ -184,9 +186,11 @@ async def test_replayer_workflow_nondeterministic_json() -> None:
 async def test_replayer_multiple_histories_fail_fast() -> None:
     with Path(__file__).with_name("test_replayer_complete_history.json").open("r") as f:
         history_json = f.read()
-    with Path(__file__).with_name("test_replayer_nondeterministic_history.json").open(
-        "r"
-    ) as f:
+    with (
+        Path(__file__)
+        .with_name("test_replayer_nondeterministic_history.json")
+        .open("r") as f
+    ):
         history_json_bad = f.read()
 
     callcount = 0
@@ -210,9 +214,11 @@ async def histories():
 async def test_replayer_multiple_histories_fail_slow() -> None:
     with Path(__file__).with_name("test_replayer_complete_history.json").open("r") as f:
         history_json = f.read()
-    with Path(__file__).with_name("test_replayer_nondeterministic_history.json").open(
-        "r"
-    ) as f:
+    with (
+        Path(__file__)
+        .with_name("test_replayer_nondeterministic_history.json")
+        .open("r") as f
+    ):
         history_json_bad = f.read()
 
     callcount = 0
@@ -389,9 +395,11 @@ async def test_replayer_command_reordering_backward_compatibility() -> None:
     to [UpdateAccepted, CompleteWorkflowExecution], and events 5 and 6 can be applied to the
     corresponding state machines.
     """
-    with Path(__file__).with_name(
-        "test_replayer_command_reordering_backward_compatibility.json"
-    ).open() as f:
+    with (
+        Path(__file__)
+        .with_name("test_replayer_command_reordering_backward_compatibility.json")
+        .open() as f
+    ):
         history = f.read()
     await Replayer(workflows=[UpdateCompletionAfterWorkflowReturn]).replay_workflow(
         WorkflowHistory.from_json("fake", history)
@@ -475,9 +483,11 @@ async def test_replayer_async_ordering() -> None:
 
 
 async def test_replayer_alternate_async_ordering() -> None:
-    with Path(__file__).with_name(
-        "test_replayer_event_tracing_alternate.json"
-    ).open() as f:
+    with (
+        Path(__file__)
+        .with_name("test_replayer_event_tracing_alternate.json")
+        .open() as f
+    ):
         history = f.read()
     await Replayer(
         workflows=[ActivityAndSignalsWhileWorkflowDown],