diff --git a/mercurial/i18n.py b/mercurial/i18n.py
--- a/mercurial/i18n.py
+++ b/mercurial/i18n.py
@@ -12,7 +12,10 @@ import locale
 import os
 import sys
 
-from . import encoding
+from . import (
+    encoding,
+    pycompat,
+)
 
 # modelled after templater.templatepath:
 if getattr(sys, 'frozen', None) is not None:
@@ -85,7 +88,8 @@ def gettext(message):
             # means u.encode(sys.getdefaultencoding()).decode(enc). Since
             # the Python encoding defaults to 'ascii', this fails if the
             # translated string use non-ASCII characters.
-            _msgcache[message] = u.encode(encoding.encoding, "replace")
+            encodingstr = pycompat.sysstr(encoding.encoding)
+            _msgcache[message] = u.encode(encodingstr, "replace")
         except LookupError:
             # An unknown encoding results in a LookupError.
             _msgcache[message] = message
diff --git a/tests/test-check-py3-compat.t b/tests/test-check-py3-compat.t
--- a/tests/test-check-py3-compat.t
+++ b/tests/test-check-py3-compat.t
@@ -120,53 +120,53 @@
   mercurial/httpconnection.py: error importing: <TypeError> Can't mix strings and bytes in path components (error at i18n.py:*)
   mercurial/httppeer.py: error importing: <TypeError> Can't mix strings and bytes in path components (error at i18n.py:*)
   mercurial/i18n.py: error importing module: <TypeError> bytes expected, not str (line *)
-  mercurial/keepalive.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/localrepo.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/lock.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/mail.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/manifest.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/match.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/mdiff.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/merge.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/minirst.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/namespaces.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/obsolete.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/patch.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/pathutil.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/peer.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/profiling.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/pushkey.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/pvec.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/registrar.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/repair.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/repoview.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/revlog.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/revset.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/scmutil.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/scmwindows.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/similar.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/simplemerge.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/sshpeer.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/sshserver.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/sslutil.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/statichttprepo.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/store.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/streamclone.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/subrepo.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/tagmerge.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/tags.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/templatefilters.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/templatekw.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/templater.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/transaction.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/ui.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/unionrepo.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/url.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/util.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
-  mercurial/verify.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
+  mercurial/keepalive.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/localrepo.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/lock.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/mail.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/manifest.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/match.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/mdiff.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/merge.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/minirst.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/namespaces.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/obsolete.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/patch.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/pathutil.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/peer.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/profiling.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/pushkey.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/pvec.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/registrar.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/repair.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/repoview.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/revlog.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/revset.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/scmutil.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/scmwindows.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/similar.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/simplemerge.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/sshpeer.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/sshserver.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/sslutil.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/statichttprepo.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/store.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/streamclone.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/subrepo.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/tagmerge.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/tags.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/templatefilters.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/templatekw.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/templater.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/transaction.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/ui.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/unionrepo.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/url.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/util.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
+  mercurial/verify.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
   mercurial/win32.py: error importing module: <ImportError> No module named 'msvcrt' (line *)
   mercurial/windows.py: error importing module: <ImportError> No module named 'msvcrt' (line *)
-  mercurial/wireproto.py: error importing: <TypeError> encode() argument 1 must be str, not bytes (error at i18n.py:*)
+  mercurial/wireproto.py: error importing: <TypeError> encode() argument 2 must be str, not bytes (error at i18n.py:*)
 
 #endif