locale is only available in Python 3.10 and later

Author: radoering

src/poetry/utils/env/base_env.py

@@ -335,8 +335,9 @@ def _run(self, cmd: list[str], **kwargs: Any) -> str:
                 subprocess.check_call(cmd, stderr=stderr, env=env, **kwargs)
                 output = ""
             else:
+                encoding = "locale" if sys.version_info >= (3, 10) else None
                 output = subprocess.check_output(
-                    cmd, stderr=stderr, env=env, text=True, encoding="locale", **kwargs
+                    cmd, stderr=stderr, env=env, text=True, encoding=encoding, **kwargs
                 )
         except CalledProcessError as e:
             raise EnvCommandError(e)