diff -r eb8092f9304f -r 8fae2cc6ee86 mercurial/dispatch.py
--- a/mercurial/dispatch.py	Mon Oct 11 17:31:27 2021 +0200
+++ b/mercurial/dispatch.py	Fri Oct 08 13:34:33 2021 -0700
@@ -253,7 +253,7 @@
         status = -1
 
     ret = _flushstdio(req.ui, err)
-    if ret:
+    if ret and not status:
         status = ret
     return status