--- a/mercurial/pycompat.py	Thu Jun 25 22:40:04 2020 +0900
+++ b/mercurial/pycompat.py	Wed Jun 24 14:44:21 2020 +0200
@@ -98,7 +98,6 @@
     import codecs
     import functools
     import io
-    import locale
     import struct
 
     if os.name == r'nt' and sys.version_info >= (3, 6):
@@ -156,16 +155,10 @@
 
     if getattr(sys, 'argv', None) is not None:
         # On POSIX, the char** argv array is converted to Python str using
-        # Py_DecodeLocale(). The inverse of this is Py_EncodeLocale(), which isn't
-        # directly callable from Python code. So, we need to emulate it.
-        # Py_DecodeLocale() calls mbstowcs() and falls back to mbrtowc() with
-        # surrogateescape error handling on failure. These functions take the
-        # current system locale into account. So, the inverse operation is to
-        # .encode() using the system locale's encoding and using the
-        # surrogateescape error handler. The only tricky part here is getting
-        # the system encoding correct, since `locale.getlocale()` can return
-        # None. We fall back to the filesystem encoding if lookups via `locale`
-        # fail, as this seems like a reasonable thing to do.
+        # Py_DecodeLocale(). The inverse of this is Py_EncodeLocale(), which
+        # isn't directly callable from Python code. In practice, os.fsencode()
+        # can be used instead (this is recommended by Python's documentation
+        # for sys.argv).
         #
         # On Windows, the wchar_t **argv is passed into the interpreter as-is.
         # Like POSIX, we need to emulate what Py_EncodeLocale() would do. But
@@ -178,19 +171,7 @@
         if os.name == r'nt':
             sysargv = [a.encode("mbcs", "ignore") for a in sys.argv]
         else:
-
-            def getdefaultlocale_if_known():
-                try:
-                    return locale.getdefaultlocale()
-                except ValueError:
-                    return None, None
-
-            encoding = (
-                locale.getlocale()[1]
-                or getdefaultlocale_if_known()[1]
-                or sys.getfilesystemencoding()
-            )
-            sysargv = [a.encode(encoding, "surrogateescape") for a in sys.argv]
+            sysargv = [fsencode(a) for a in sys.argv]
 
     bytechr = struct.Struct('>B').pack
     byterepr = b'%r'.__mod__