chg in a pipeline

[Marcus Harnisch]

When trying to transplant changes from one repo into another using a 
simple pipe:

   (cd ../orig && hg export -r <revset>) | hg  import -

gives strange error messages when chg used instead (e.g. aliased). The 
error does not seem to occur with a small demo repository, so I suspect 
a race condition.

Not sure if this is expected but would there be a possibility to catch this?

Thanks,
Marcus

   Traceback (most recent call last):
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/commandserver.py", 
line 510, in _serverequest
       sv.cleanup()
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/chgserver.py", 
line 383, in cleanup
       self._restoreio()
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/chgserver.py", 
line 446, in _restoreio
       newfp.close()
   BrokenPipeError: [Errno 32] Broken pipe
   Traceback (most recent call last):
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/commandserver.py", 
line 694, in _acceptnewconnection
       self._runworker(conn)
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/commandserver.py", 
line 740, in _runworker
       _serverequest(
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/commandserver.py", 
line 510, in _serverequest
       sv.cleanup()
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/chgserver.py", 
line 383, in cleanup
       self._restoreio()
     File 
"/home/user1/.local/lib/python3.8/site-packages/mercurial/chgserver.py", 
line 446, in _restoreio
       newfp.close()
   BrokenPipeError: [Errno 32] Broken pipe