diff -r 701341f57ceb -r 24cd5b0ba5b3 contrib/automation/hgautomation/windows.py
--- a/contrib/automation/hgautomation/windows.py	Thu Jul 25 21:28:29 2019 +0900
+++ b/contrib/automation/hgautomation/windows.py	Sun Jul 28 18:16:08 2019 -0700
@@ -180,7 +180,11 @@
             'ssh://%s/c:/hgdev/src' % public_ip,
         ]
 
-        subprocess.run(args, cwd=str(hg_repo), env=env, check=True)
+        res = subprocess.run(args, cwd=str(hg_repo), env=env)
+
+        # Allow 1 (no-op) to not trigger error.
+        if res.returncode not in (0, 1):
+            res.check_returncode()
 
         run_powershell(winrm_client,
                        HG_UPDATE_CLEAN.format(revision=full_revision))