Setting this to resolved. Specific other problems should probably be reported
separately.

The redirection for ssh and http servers was implemented in 323b9c55b328.

It seems like some of these problems still persist, though.

The basic problem is that when hg talks to a remote repo (over ssh or HTTP), it
uses stdin and stdout for its protocol.  If a hook prints something to stdout it
can mess things up.

A quick workaround is to redirect the output of your hook to stderr:

[hooks]
changegroup = pull-diffstat 1>&2

I'm renaming this issue to make it more general.  We'll probably have to
redirect the stdout from hooks to stderr - at least if we're the server in a
ssh/HTTP connection, but it may be easier to just do this every time.

When pushing to a Linux box with a diffstat hook enabled:

[hooks]
changegroup = pull-diffstat

I get the following backtrace:

C:\hg\hg-release\.hg\patches>hg push
pushing to ssh://steve@trixy/tools/mq-win32-hg-plus
searching for changes
** unknown exception encountered, details follow
** report bug details to http://www.selenic.com/mercurial/bts
** or mercurial@selenic.com
** Mercurial Distributed SCM (version 6bc09d998af2)
Traceback (most recent call last):
  File "hg", line 25, in <module>
  File "mercurial\dispatch.pyc", line 20, in run
  File "mercurial\dispatch.pyc", line 29, in dispatch
  File "mercurial\dispatch.pyc", line 45, in _runcatch
  File "mercurial\dispatch.pyc", line 348, in _dispatch
  File "mercurial\dispatch.pyc", line 401, in _runcommand
  File "mercurial\dispatch.pyc", line 357, in checkargs
  File "mercurial\dispatch.pyc", line 340, in <lambda>
  File "mercurial\commands.pyc", line 2125, in push
  File "hgext\mq.pyc", line 2072, in push
  File "mercurial\localrepo.pyc", line 1381, in push
  File "mercurial\localrepo.pyc", line 1461, in push_unbundle
  File "mercurial\sshrepo.pyc", line 199, in unbundle
ValueError: invalid literal for int() with base 10: 'diffstat for e89549c2e8e7 t
o f159b5091958\n'
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 4 changes to 4 files

The push succeeded, regardless of the error message.  This seems to be
independent of the ssh client I use, and it happens whether I push a
normal repo or a patch queue repo.

% hg version
Mercurial Distributed SCM (version bbdcdc7f170e)