Use tomllib on Python 3.11

CHANGES.md

@@ -45,6 +45,9 @@
 
 <!-- Changes to how Black is packaged, such as dependency requirements -->
 
+- On Python 3.11 and newer, use the standard library's `tomllib` instead of `tomli`
+  (#2903)
+
 ### Parser
 
 <!-- Changes to the parser or to version autodetection -->

setup.py

@@ -99,7 +99,7 @@ def find_python_files(base: Path) -> List[Path]:
     install_requires=[
         "click>=8.0.0",
         "platformdirs>=2",
-        "tomli>=1.1.0",
+        "tomli>=1.1.0; python_version < '3.11'",
         "typed-ast>=1.4.2; python_version < '3.8' and implementation_name == 'cpython'",
         "pathspec>=0.9.0",
         "dataclasses>=0.6; python_version < '3.7'",

src/black/files.py

@@ -20,7 +20,11 @@
 from mypy_extensions import mypyc_attr
 from pathspec import PathSpec
 from pathspec.patterns.gitwildmatch import GitWildMatchPatternError
-import tomli
+
+if sys.version_info >= (3, 11):
+    import tomllib
+else:
+    import tomli as tomllib
 
 from black.output import err
 from black.report import Report
@@ -97,10 +101,10 @@ def find_pyproject_toml(path_search_start: Tuple[str, ...]) -> Optional[str]:
 def parse_pyproject_toml(path_config: str) -> Dict[str, Any]:
     """Parse a pyproject toml file, pulling out relevant parts for Black
 
-    If parsing fails, will raise a tomli.TOMLDecodeError
+    If parsing fails, will raise a tomllib.TOMLDecodeError
     """
     with open(path_config, "rb") as f:
-        pyproject_toml = tomli.load(f)
+        pyproject_toml = tomllib.load(f)
     config = pyproject_toml.get("tool", {}).get("black", {})
     return {k.replace("--", "").replace("-", "_"): v for k, v in config.items()}