typing for diff

Before:

    Diff Coverage
    Diff: eb00182...HEAD, staged and unstaged changes
    -------------
    src/_pytest/mark/structures.py (0.0%): Missing lines 274
    src/_pytest/nodes.py (100%)
    src/_pytest/python.py (72.2%): Missing lines 290,301,1518-1520
    testing/test_mark.py (61.5%): Missing lines 967,981,984,989,992-993,995,997-1000,1014-1015,1017-1018
    -------------
    Total:   63 lines
    Missing: 21 lines
    Coverage: 66%

After:

    Diff Coverage
    Diff: eb00182...HEAD, staged and unstaged changes
    -------------
    src/_pytest/mark/structures.py (100%)
    src/_pytest/nodes.py (100%)
    src/_pytest/python.py (95.7%): Missing lines 1519
    testing/test_mark.py (64.1%): Missing lines 967,984,989,992-993,995,997-1000,1014-1015,1017-1018
    -------------
    Total:   72 lines
    Missing: 15 lines
    Coverage: 79%

Author: blueyed

src/_pytest/mark/structures.py

@@ -17,12 +17,17 @@
 from .._code.source import getfslineno
 from ..compat import ascii_escaped
 from ..compat import NOTSET
+from ..compat import TYPE_CHECKING
 from _pytest.outcomes import fail
 from _pytest.warning_types import PytestUnknownMarkWarning
 
 EMPTY_PARAMETERSET_OPTION = "empty_parameter_set_mark"
 
 
+if TYPE_CHECKING:
+    from .. import nodes
+
+
 def istestfunc(func):
     return (
         hasattr(func, "__call__")
@@ -271,7 +276,7 @@ def __call__(self, *args: object, **kwargs: object):
         return self.with_args(*args, **kwargs)
 
 
-def get_unpacked_marks(obj) -> List[Mark]:
+def get_unpacked_marks(obj: object) -> List[Mark]:
     """
     obtain the unpacked marks that are stored on an object
     """
@@ -371,7 +376,7 @@ def __getattr__(self, name: str) -> MarkDecorator:
 
 
 class NodeKeywords(MutableMapping):
-    def __init__(self, node):
+    def __init__(self, node: "nodes.Node") -> None:
         self.node = node
         self.parent = node.parent
         self._markers = {node.name: True}

src/_pytest/nodes.py

@@ -3,6 +3,7 @@
 from functools import lru_cache
 from typing import Any
 from typing import Dict
+from typing import Iterator
 from typing import List
 from typing import Optional
 from typing import Set
@@ -264,7 +265,7 @@ def add_marker(
         else:
             self._own_markers[0].insert(0, marker_.mark)
 
-    def iter_markers(self, name=None):
+    def iter_markers(self, name: Optional[str] = None) -> Iterator[Mark]:
         """
         :param name: if given, filter the results by the name attribute
 

src/_pytest/python.py

@@ -279,19 +279,19 @@ class PyobjMixin:
         _own_markers = ([], [])  # type: Tuple[List[Mark], List[Mark]]
 
     @property
-    def obj(self):
+    def obj(self) -> object:
         """Underlying Python object."""
         obj = getattr(self, "_obj", None)
         if obj is None:
             self._obj = obj = self._getobj()
         return obj
 
     @obj.setter
-    def obj(self, value) -> None:
+    def obj(self, value: object) -> None:
         self._obj = value
         self._obj_markers = None
 
-    def _getobj(self):
+    def _getobj(self) -> object:
         """Gets the underlying Python object. May be overwritten by subclasses."""
         return getattr(self.parent.obj, self.name)
 
@@ -791,13 +791,13 @@ def hasnew(obj):
 
 
 class CallSpec2:
-    def __init__(self, metafunc):
+    def __init__(self, metafunc: "Metafunc") -> None:
         self.metafunc = metafunc
         self.funcargs = {}
         self._idlist = []
         self.params = {}
         self._arg2scopenum = {}  # used for sorting parametrized resources
-        self.marks = []
+        self.marks = []  # type: List[Mark]
         self.indices = {}
 
     def copy(self):
@@ -1448,7 +1448,7 @@ def __init__(
         config=None,
         callspec: Optional[CallSpec2] = None,
         callobj=NOTSET,
-        keywords=None,
+        keywords: Optional[Iterable[str]] = None,
         session=None,
         fixtureinfo: Optional[FuncFixtureInfo] = None,
         originalname=None,