diff --git a/contrib/hgperf b/contrib/hgperf
--- a/contrib/hgperf
+++ b/contrib/hgperf
@@ -94,4 +94,4 @@
 
 dispatch.runcommand = runcommand
 
-dispatch.run()
+sys.exit(dispatch.run())
diff --git a/hg b/hg
--- a/hg
+++ b/hg
@@ -38,4 +38,4 @@
     sys.exit(-1)
 
 from mercurial import dispatch
-dispatch.run()
+sys.exit(dispatch.run())
diff --git a/mercurial/dispatch.py b/mercurial/dispatch.py
--- a/mercurial/dispatch.py
+++ b/mercurial/dispatch.py
@@ -145,7 +145,7 @@
             # There's not much we can do about I/O errors at this point.
             code = -1
 
-    sys.exit(code & 255)
+    return code & 255
 
 if pycompat.ispy3:
     def _initstdio():