Improve typing

Fix #1057

src/xdist/plugin.py

@@ -1,5 +1,8 @@
+from __future__ import annotations
+
 import os
 import sys
+from typing import Literal
 import uuid
 import warnings
 
@@ -10,7 +13,7 @@ _sys_path = list(sys.path)  # freeze a copy of sys.path at interpreter startup
 
 
 @pytest.hookimpl
-def pytest_xdist_auto_num_workers(config):
+def pytest_xdist_auto_num_workers(config: pytest.Config) -> int:
     env_var = os.environ.get("PYTEST_XDIST_AUTO_NUM_WORKERS")
     if env_var:
         try:
@@ -25,14 +28,14 @@ def pytest_xdist_auto_num_workers(config):
     except ImportError:
         pass
     else:
-        use_logical = config.option.numprocesses == "logical"
+        use_logical: bool = config.option.numprocesses == "logical"
         count = psutil.cpu_count(logical=use_logical) or psutil.cpu_count()
         if count:
             return count
     try:
         from os import sched_getaffinity
 
-        def cpu_count():
+        def cpu_count() -> int:
             return len(sched_getaffinity(0))
 
     except ImportError:
@@ -40,7 +43,7 @@ def pytest_xdist_auto_num_workers(config):
             # workaround https://bitbucket.org/pypy/pypy/issues/2375
             return 2
         try:
-            from os import cpu_count
+            from os import cpu_count  # type: ignore[assignment]
         except ImportError:
             from multiprocessing import cpu_count
     try:
@@ -50,15 +53,15 @@ def pytest_xdist_auto_num_workers(config):
     return n if n else 1
 
 
-def parse_numprocesses(s):
+def parse_numprocesses(s: str) -> int | Literal["auto", "logical"]:
     if s in ("auto", "logical"):
-        return s
+        return s  # type: ignore[return-value]
     elif s is not None:
         return int(s)
 
 
 @pytest.hookimpl
-def pytest_addoption(parser):
+def pytest_addoption(parser: pytest.Parser) -> None:
     # 'Help' formatting (same rules as pytest's):
     # Start with capitalized letters.
     # If a single phrase, do not end with period. If more than one phrase, all phrases end with periods.
@@ -206,7 +209,7 @@ def pytest_addoption(parser):
 
 
 @pytest.hookimpl
-def pytest_addhooks(pluginmanager):
+def pytest_addhooks(pluginmanager: pytest.PytestPluginManager) -> None:
     from xdist import newhooks
 
     pluginmanager.add_hookspecs(newhooks)
@@ -218,7 +221,7 @@ def pytest_addhooks(pluginmanager):
 
 
 @pytest.hookimpl(trylast=True)
-def pytest_configure(config):
+def pytest_configure(config: pytest.Config) -> None:
     config_line = (
         "xdist_group: specify group for tests should run in same session."
         "in relation to one another. Provided by pytest-xdist."
@@ -256,16 +259,13 @@ def pytest_configure(config):
         config.issue_config_time_warning(warning, 2)
 
 
-def _is_distribution_mode(config):
-    """Return `True` if distribution mode is on, `False` otherwise.
-
-    :param config: the `pytest` `config` object
-    """
-    return config.getoption("dist") != "no" and config.getoption("tx")
+def _is_distribution_mode(config: pytest.Config) -> bool:
+    """Whether distribution mode is on."""
+    return config.getoption("dist") != "no" and bool(config.getoption("tx"))
 
 
 @pytest.hookimpl(tryfirst=True)
-def pytest_cmdline_main(config):
+def pytest_cmdline_main(config: pytest.Config) -> None:
     if config.option.distload:
         config.option.dist = "load"
 
@@ -302,7 +302,9 @@ def pytest_cmdline_main(config):
 # -------------------------------------------------------------------------
 
 
-def is_xdist_worker(request_or_session) -> bool:
+def is_xdist_worker(
+    request_or_session: pytest.FixtureRequest | pytest.Session,
+) -> bool:
     """Return `True` if this is an xdist worker, `False` otherwise.
 
     :param request_or_session: the `pytest` `request` or `session` object
@@ -310,7 +312,9 @@ def is_xdist_worker(request_or_session) -> bool:
     return hasattr(request_or_session.config, "workerinput")
 
 
-def is_xdist_controller(request_or_session) -> bool:
+def is_xdist_controller(
+    request_or_session: pytest.FixtureRequest | pytest.Session,
+) -> bool:
     """Return `True` if this is the xdist controller, `False` otherwise.
 
     Note: this method also returns `False` when distribution has not been
@@ -328,7 +332,9 @@ def is_xdist_controller(request_or_session) -> bool:
 is_xdist_master = is_xdist_controller
 
 
-def get_xdist_worker_id(request_or_session):
+def get_xdist_worker_id(
+    request_or_session: pytest.FixtureRequest | pytest.Session,
+) -> str:
     """Return the id of the current worker ('gw0', 'gw1', etc) or 'master'
     if running on the controller node.
 
@@ -338,14 +344,15 @@ def get_xdist_worker_id(request_or_session):
     :param request_or_session: the `pytest` `request` or `session` object
     """
     if hasattr(request_or_session.config, "workerinput"):
-        return request_or_session.config.workerinput["workerid"]
+        workerid: str = request_or_session.config.workerinput["workerid"]
+        return workerid
     else:
         # TODO: remove "master", ideally for a None
         return "master"
 
 
 @pytest.fixture(scope="session")
-def worker_id(request):
+def worker_id(request: pytest.FixtureRequest) -> str:
     """Return the id of the current worker ('gw0', 'gw1', etc) or 'master'
     if running on the master node.
     """
@@ -354,9 +361,10 @@ def worker_id(request):
 
 
 @pytest.fixture(scope="session")
-def testrun_uid(request):
+def testrun_uid(request: pytest.FixtureRequest) -> str:
     """Return the unique id of the current test."""
     if hasattr(request.config, "workerinput"):
-        return request.config.workerinput["testrunuid"]
+        testrunid: str = request.config.workerinput["testrunuid"]
+        return testrunid
     else:
         return uuid.uuid4().hex