Replaced typing.Self with typing_extensions.Self (#12744)

Fix incorrect Self import from typing instead of typing_extensions.

---------

Co-authored-by: Bruno Oliveira <[email protected]>

Author: Avasam

changelog/12744.bugfix.rst

@@ -0,0 +1 @@
+Fixed typing compatibility with Python 3.9 or less -- replaced `typing.Self` with `typing_extensions.Self` -- by :user:`Avasam`

src/_pytest/doctest.py

@@ -44,7 +44,8 @@
 
 if TYPE_CHECKING:
     import doctest
-    from typing import Self
+
+    from typing_extensions import Self
 
 DOCTEST_REPORT_CHOICE_NONE = "none"
 DOCTEST_REPORT_CHOICE_CDIFF = "cdiff"

src/_pytest/nodes.py

@@ -43,7 +43,7 @@
 
 
 if TYPE_CHECKING:
-    from typing import Self
+    from typing_extensions import Self
 
     # Imported here due to circular import.
     from _pytest.main import Session

src/_pytest/python.py

@@ -78,7 +78,7 @@
 
 
 if TYPE_CHECKING:
-    from typing import Self
+    from typing_extensions import Self
 
 
 def pytest_addoption(parser: Parser) -> None: