Prefer sys.version_info for feature checks (#11736)

Author: smithdc1

sphinx/cmd/make_mode.py

@@ -25,9 +25,9 @@
 )
 from sphinx.util.osutil import rmtree
 
-try:
-    from contextlib import chdir  # type: ignore[attr-defined]
-except ImportError:
+if sys.version_info >= (3, 11):
+    from contextlib import chdir
+else:
     from sphinx.util.osutil import _chdir as chdir
 
 if TYPE_CHECKING:

sphinx/config.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+import sys
 import time
 import traceback
 import types
@@ -14,9 +15,9 @@
 from sphinx.util.osutil import fs_encoding
 from sphinx.util.typing import NoneType
 
-try:
-    from contextlib import chdir  # type: ignore[attr-defined]
-except ImportError:
+if sys.version_info >= (3, 11):
+    from contextlib import chdir
+else:
     from sphinx.util.osutil import _chdir as chdir
 
 if TYPE_CHECKING:

sphinx/util/typing.py

@@ -15,9 +15,9 @@
 if TYPE_CHECKING:
     import enum
 
-try:
-    from types import UnionType  # type: ignore[attr-defined] # python 3.10 or above
-except ImportError:
+if sys.version_info >= (3, 10):
+    from types import UnionType
+else:
     UnionType = None
 
 # classes that have incorrect __module__