"show" completion et al spammy when binaries don't exist

["Mikael Magnusson" <mikachu@gmail.com>]

I was looking at another window while writing and typed
show show gi<tab>
instead of git show gi<tab> and got the following:
% show show gi_mh:1: command not found: mhpath
_mh:1: command not found: mhparam
_mh:1: command not found: mhpath
_mh:1: command not found: mhparam
_mh:1: command not found: mhpath
_mh:1: command not found: mhparam
_mh:1: command not found: mhpath
_mh:1: command not found: mhparam
                           show show gi<cursor here>
---- no match for: `sequence' or `corrections'

After the error messages the prompt wasn't redrawn correctly, but I
think that is expected. In _mh all commands are called with 2>
/dev/null, but that doesn't help much since zsh is the one to print
the messages. Which leads me to ask, is the stderr output of
completion scripts ever wanted in the terminal? Maybe it should be
redirected more centrally? Putting
which mhpath >& /dev/null || return
on the first line of _mh fixes the problem, I don't know if some other
method would be preferred. It seems _git also suffers from this
problem. Typing apt-get install <tab> repeatedly inserts a space. Are
these sort of things to be considered as problems, or am I stupid to
press tab after a command I don't have?

-- 
Mikael Magnusson