tests/test-notify-changegroup

prepush: add more precise error messages

Part of the patch is from [e-mail]

- indicate the branch name where there are multiple heads
- give better advice when hitting a possible race, where new heads are added
  between discovery and the call to branchmap(). In that case, asking the user
  to merge isn't helpful, since only remote has the changes.

#!/bin/sh

cat <<EOF >> $HGRCPATH
[extensions]
notify=

[hooks]
changegroup.notify = python:hgext.notify.hook

[notify]
sources = push
diffstat = False
maxsubject = 200

[usersubs]
foo@bar = *

[reposubs]
* = baz
EOF

hg init a

echo % clone
hg --traceback clone a b

echo a > b/a
echo % commit
hg --traceback --cwd b commit -Ama

echo a >> b/a
echo % commit
hg --traceback --cwd b commit -Amb

echo % push
hg --traceback --cwd b push ../a 2>&1 |
    python -c 'import sys,re; print re.sub("\n\t", " ", sys.stdin.read()),' |
    sed -e 's/\(Message-Id:\).*/\1/' \
        -e 's/changeset \([0-9a-f]* *\)in .*test-notif/changeset \1in test-notif/' \
        -e 's/^Subject: .*test-notify/Subject: test-notify/' \
        -e 's/^details: .*test-notify/details: test-notify/' \
        -e 's/^Date:.*/Date:/'