tests/test-hgweb-descend-empties

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
# Test chains of near empty directories, terminating 3 different ways:
# - a1: file at level 4 (deepest)
# - b1: two dirs at level 3
# - e1: file at level 2

echo % Set up the repo
hg init test
cd test
mkdir -p a1/a2/a3/a4
mkdir -p b1/b2/b3/b4
mkdir -p b1/b2/c3/c4
mkdir -p d1/d2/d3/d4
echo foo > a1/a2/a3/a4/foo
echo foo > b1/b2/b3/b4/foo
echo foo > b1/b2/c3/c4/foo
echo foo > d1/d2/d3/d4/foo
echo foo > d1/d2/foo
hg ci -Ama

hg serve -n test -p $HGPORT -d --pid-file=hg.pid -E errors.log
cat hg.pid >> $DAEMON_PIDS

echo % manifest with descending
"$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT '/file'

echo % ERRORS ENCOUNTERED
cat errors.log