Type annotate some hookspecs & impls

src/_pytest/assertion/__init__.py

@@ -9,12 +9,13 @@
 from _pytest.assertion import util
 from _pytest.compat import TYPE_CHECKING
 from _pytest.config import hookimpl
+from _pytest.config.argparsing import Parser
 
 if TYPE_CHECKING:
     from _pytest.main import Session
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     group = parser.getgroup("debugconfig")
     group.addoption(
         "--assert",
@@ -162,7 +163,7 @@ def call_assertion_pass_hook(lineno, orig, expl):
     util._reprcompare, util._assertion_pass = saved_assert_hooks
 
 
-def pytest_sessionfinish(session):
+def pytest_sessionfinish(session: "Session") -> None:
     assertstate = getattr(session.config, "_assertstate", None)
     if assertstate:
         if assertstate.hook is not None:

src/_pytest/cacheprovider.py

@@ -12,6 +12,7 @@
 from typing import List
 from typing import Optional
 from typing import Set
+from typing import Union
 
 import attr
 import py
@@ -24,6 +25,8 @@
 from _pytest import nodes
 from _pytest._io import TerminalWriter
 from _pytest.config import Config
+from _pytest.config import ExitCode
+from _pytest.config.argparsing import Parser
 from _pytest.main import Session
 from _pytest.python import Module
 
@@ -316,11 +319,12 @@ def pytest_collection_modifyitems(self, session, config, items):
             else:
                 self._report_status += "not deselecting items."
 
-    def pytest_sessionfinish(self, session):
+    def pytest_sessionfinish(self, session: Session) -> None:
         config = self.config
         if config.getoption("cacheshow") or hasattr(config, "slaveinput"):
             return
 
+        assert config.cache is not None
         saved_lastfailed = config.cache.get("cache/lastfailed", {})
         if saved_lastfailed != self.lastfailed:
             config.cache.set("cache/lastfailed", self.lastfailed)
@@ -358,15 +362,15 @@ def pytest_collection_modifyitems(
     def _get_increasing_order(self, items):
         return sorted(items, key=lambda item: item.fspath.mtime(), reverse=True)
 
-    def pytest_sessionfinish(self, session):
+    def pytest_sessionfinish(self, session: Session) -> None:
         config = self.config
         if config.getoption("cacheshow") or hasattr(config, "slaveinput"):
             return
 
         config.cache.set("cache/nodeids", self.cached_nodeids)
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     group = parser.getgroup("general")
     group.addoption(
         "--lf",
@@ -424,16 +428,18 @@ def pytest_addoption(parser):
     )
 
 
-def pytest_cmdline_main(config):
+def pytest_cmdline_main(config: Config) -> Optional[Union[int, ExitCode]]:
     if config.option.cacheshow:
         from _pytest.main import wrap_session
 
         return wrap_session(config, cacheshow)
+    return None
 
 
 @pytest.hookimpl(tryfirst=True)
 def pytest_configure(config: Config) -> None:
-    config.cache = Cache.for_config(config)
+    # Type ignored: pending mechanism to store typed objects scoped to config.
+    config.cache = Cache.for_config(config)  # type: ignore # noqa: F821
     config.pluginmanager.register(LFPlugin(config), "lfplugin")
     config.pluginmanager.register(NFPlugin(config), "nfplugin")
 

src/_pytest/capture.py

@@ -19,6 +19,7 @@
 from _pytest.compat import CaptureIO
 from _pytest.compat import TYPE_CHECKING
 from _pytest.config import Config
+from _pytest.config.argparsing import Parser
 from _pytest.fixtures import FixtureRequest
 
 if TYPE_CHECKING:
@@ -29,7 +30,7 @@
 patchsysdict = {0: "stdin", 1: "stdout", 2: "stderr"}
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     group = parser.getgroup("general")
     group._addoption(
         "--capture",

src/_pytest/config/__init__.py

@@ -393,7 +393,7 @@ def hasplugin(self, name):
         """Return True if the plugin with the given name is registered."""
         return bool(self.get_plugin(name))
 
-    def pytest_configure(self, config):
+    def pytest_configure(self, config: "Config") -> None:
         # XXX now that the pluginmanager exposes hookimpl(tryfirst...)
         # we should remove tryfirst/trylast as markers
         config.addinivalue_line(
@@ -831,7 +831,9 @@ def _ensure_unconfigure(self):
     def get_terminal_writer(self):
         return self.pluginmanager.get_plugin("terminalreporter")._tw
 
-    def pytest_cmdline_parse(self, pluginmanager, args):
+    def pytest_cmdline_parse(
+        self, pluginmanager: PytestPluginManager, args: List[str]
+    ) -> object:
         try:
             self.parse(args)
         except UsageError:

src/_pytest/debugging.py

@@ -4,7 +4,10 @@
 import sys
 
 from _pytest import outcomes
+from _pytest.config import Config
 from _pytest.config import hookimpl
+from _pytest.config import PytestPluginManager
+from _pytest.config.argparsing import Parser
 from _pytest.config.exceptions import UsageError
 
 
@@ -19,7 +22,7 @@ def _validate_usepdb_cls(value):
     return (modname, classname)
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     group = parser.getgroup("general")
     group._addoption(
         "--pdb",
@@ -43,7 +46,7 @@ def pytest_addoption(parser):
     )
 
 
-def pytest_configure(config):
+def pytest_configure(config: Config) -> None:
     import pdb
 
     if config.getvalue("trace"):
@@ -73,8 +76,8 @@ def fin():
 class pytestPDB:
     """ Pseudo PDB that defers to the real pdb. """
 
-    _pluginmanager = None
-    _config = None
+    _pluginmanager = None  # type: PytestPluginManager
+    _config = None  # type: Config
     _saved = []  # type: list
     _recursive_debug = 0
     _wrapped_pdb_cls = None

src/_pytest/doctest.py

@@ -23,6 +23,7 @@
 from _pytest._io import TerminalWriter
 from _pytest.compat import safe_getattr
 from _pytest.compat import TYPE_CHECKING
+from _pytest.config.argparsing import Parser
 from _pytest.fixtures import FixtureRequest
 from _pytest.outcomes import OutcomeException
 from _pytest.python_api import approx
@@ -52,7 +53,7 @@
 CHECKER_CLASS = None  # type: Optional[Type[doctest.OutputChecker]]
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     parser.addini(
         "doctest_optionflags",
         "option flags for doctests",
@@ -102,7 +103,7 @@ def pytest_addoption(parser):
     )
 
 
-def pytest_unconfigure():
+def pytest_unconfigure() -> None:
     global RUNNER_CLASS
 
     RUNNER_CLASS = None

src/_pytest/faulthandler.py

@@ -3,9 +3,11 @@
 import sys
 
 import pytest
+from _pytest.config import Config
+from _pytest.config.argparsing import Parser
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     help = (
         "Dump the traceback of all threads if a test takes "
         "more than TIMEOUT seconds to finish.\n"
@@ -14,7 +16,7 @@ def pytest_addoption(parser):
     parser.addini("faulthandler_timeout", help, default=0.0)
 
 
-def pytest_configure(config):
+def pytest_configure(config: Config) -> None:
     import faulthandler
 
     if not faulthandler.is_enabled():
@@ -42,23 +44,25 @@ class FaultHandlerHooks:
     """Implements hooks that will actually install fault handler before tests execute,
     as well as correctly handle pdb and internal errors."""
 
-    def pytest_configure(self, config):
+    def pytest_configure(self, config: Config) -> None:
         import faulthandler
 
         stderr_fd_copy = os.dup(self._get_stderr_fileno())
-        config.fault_handler_stderr = os.fdopen(stderr_fd_copy, "w")
-        faulthandler.enable(file=config.fault_handler_stderr)
+        fault_handler_stderr = os.fdopen(stderr_fd_copy, "w")
+        # Type ignored: pending mechanism to store typed objects scoped to config.
+        config.fault_handler_stderr = fault_handler_stderr  # type: ignore # noqa: F821
+        faulthandler.enable(file=fault_handler_stderr)
 
-    def pytest_unconfigure(self, config):
+    def pytest_unconfigure(self, config: Config) -> None:
         import faulthandler
 
         faulthandler.disable()
         # close our dup file installed during pytest_configure
         # re-enable the faulthandler, attaching it to the default sys.stderr
         # so we can see crashes after pytest has finished, usually during
         # garbage collection during interpreter shutdown
-        config.fault_handler_stderr.close()
-        del config.fault_handler_stderr
+        config.fault_handler_stderr.close()  # type: ignore[attr-defined] # noqa: F821
+        del config.fault_handler_stderr  # type: ignore[attr-defined] # noqa: F821
         faulthandler.enable(file=self._get_stderr_fileno())
 
     @staticmethod

src/_pytest/fixtures.py

@@ -28,6 +28,7 @@
 from _pytest.compat import NOTSET
 from _pytest.compat import safe_getattr
 from _pytest.compat import TYPE_CHECKING
+from _pytest.config.argparsing import Parser
 from _pytest.deprecated import FIXTURE_POSITIONAL_ARGUMENTS
 from _pytest.deprecated import FUNCARGNAMES
 from _pytest.mark import ParameterSet
@@ -47,7 +48,7 @@ class PseudoFixtureDef:
     scope = attr.ib()
 
 
-def pytest_sessionstart(session: "Session"):
+def pytest_sessionstart(session: "Session") -> None:
     import _pytest.python
     import _pytest.nodes
 
@@ -1200,7 +1201,7 @@ def test_foo(pytestconfig):
     return request.config
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     parser.addini(
         "usefixtures",
         type="args",

src/_pytest/helpconfig.py

@@ -2,11 +2,16 @@
 import os
 import sys
 from argparse import Action
+from typing import Optional
+from typing import Union
 
 import py
 
 import pytest
+from _pytest.config import Config
+from _pytest.config import ExitCode
 from _pytest.config import PrintHelp
+from _pytest.config.argparsing import Parser
 
 
 class HelpAction(Action):
@@ -36,7 +41,7 @@ def __call__(self, parser, namespace, values, option_string=None):
             raise PrintHelp
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: Parser) -> None:
     group = parser.getgroup("debugconfig")
     group.addoption(
         "--version",
@@ -106,7 +111,7 @@ def pytest_cmdline_parse():
         undo_tracing = config.pluginmanager.enable_tracing()
         sys.stderr.write("writing pytestdebug information to %s\n" % path)
 
-        def unset_tracing():
+        def unset_tracing() -> None:
             debugfile.close()
             sys.stderr.write("wrote pytestdebug information to %s\n" % debugfile.name)
             config.trace.root.setwriter(None)
@@ -127,7 +132,7 @@ def showversion(config):
             sys.stderr.write(line + "\n")
 
 
-def pytest_cmdline_main(config):
+def pytest_cmdline_main(config: Config) -> Optional[Union[int, ExitCode]]:
     if config.option.version:
         showversion(config)
         return 0
@@ -136,9 +141,10 @@ def pytest_cmdline_main(config):
         showhelp(config)
         config._ensure_unconfigure()
         return 0
+    return None
 
 
-def showhelp(config):
+def showhelp(config: Config) -> None:
     import textwrap
 
     reporter = config.pluginmanager.get_plugin("terminalreporter")