--- a/mercurial/dirstate.py	Fri Nov 15 10:16:27 2019 -0800
+++ b/mercurial/dirstate.py	Mon Nov 18 17:34:44 2019 +0100
@@ -1112,13 +1112,13 @@
             # Force Rayon (Rust parallelism library) to respect the number of
             # workers. This is a temporary workaround until Rust code knows
             # how to read the config file.
-            numcpus = self._ui.configint("worker", "numcpus")
+            numcpus = self._ui.configint(b"worker", b"numcpus")
             if numcpus is not None:
                 encoding.environ.setdefault(
                     b'RAYON_NUM_THREADS', b'%d' % numcpus
                 )
 
-            workers_enabled = self._ui.configbool("worker", "enabled", True)
+            workers_enabled = self._ui.configbool(b"worker", b"enabled", True)
             if not workers_enabled:
                 encoding.environ[b"RAYON_NUM_THREADS"] = b"1"