Use tomllib on Python 3.11 (#9741)

Author: hauntsaninja

changelog/9741.improvement.rst

@@ -0,0 +1,3 @@
+On Python 3.11, use the standard library's :mod:`tomllib` to parse TOML.
+
+:mod:`tomli`` is no longer a dependency on Python 3.11.

setup.cfg

@@ -46,10 +46,10 @@ install_requires =
     packaging
     pluggy>=0.12,<2.0
     py>=1.8.2
-    tomli>=1.0.0
     atomicwrites>=1.0;sys_platform=="win32"
     colorama;sys_platform=="win32"
     importlib-metadata>=0.12;python_version<"3.8"
+    tomli>=1.0.0;python_version<"3.11"
 python_requires = >=3.7
 package_dir =
     =src

src/_pytest/config/findpaths.py

@@ -1,4 +1,5 @@
 import os
+import sys
 from pathlib import Path
 from typing import Dict
 from typing import Iterable
@@ -64,12 +65,15 @@ def load_config_dict_from_file(
 
     # '.toml' files are considered if they contain a [tool.pytest.ini_options] table.
     elif filepath.suffix == ".toml":
-        import tomli
+        if sys.version_info >= (3, 11):
+            import tomllib
+        else:
+            import tomli as tomllib
 
         toml_text = filepath.read_text(encoding="utf-8")
         try:
-            config = tomli.loads(toml_text)
-        except tomli.TOMLDecodeError as exc:
+            config = tomllib.loads(toml_text)
+        except tomllib.TOMLDecodeError as exc:
             raise UsageError(f"{filepath}: {exc}") from exc
 
         result = config.get("tool", {}).get("pytest", {}).get("ini_options", None)