tests/test-parentrevspec

prepush: rewrite most of the code from scratch

For servers with branchmap support, the algorithm now works as follows:

1. A list of branches in outgoing changesets is created.
2. Using the remote branchmap, a check for new branches is performed.
3. A map (from branch to head list) of locally known remote heads before
   the push is created, and one which, after step 4, will contain the locally
   known remote heads after the push.
4. The post-push head map is updated with the outgoing changesets, using the
   branch cache update mechanism.
5. A check for new heads is performed, by comparing the length of the head list
   before and after push, for each branch. If there are new heads, an error
   depending on whether or not there are incoming changes on the branch,
   is returned.
6. If the push is allowed, a warning is written if there are incoming changes
   on any branches involved in the push.

For old servers, an algorithm similar to step 4-6 above is used to check for
new topological heads only.

Two bugs are also fixed:
1. Sometimes you would be allowed to push new branch heads without --force.
   A test for this case was added.
2. You would get the "note: unsynced remote changes!" warning if there were any
   incoming changesets, even if they were on unrelated branches.

#!/bin/sh

commit()
{
    msg=$1
    p1=$2
    p2=$3

    if [ "$p1" ]; then
	hg up -qC $p1
    fi

    if [ "$p2" ]; then
	HGMERGE=true hg merge -q $p2
    fi

    echo >> foo

    hg commit -qAm "$msg"
}

hg init repo
cd repo

echo '[extensions]' > .hg/hgrc
echo 'parentrevspec =' >> .hg/hgrc

commit '0: add foo'
commit '1: change foo 1'
commit '2: change foo 2a'
commit '3: change foo 3a'
commit '4: change foo 2b' 1
commit '5: merge' 3 4
commit '6: change foo again'

hg log --template '{rev}:{node|short} {parents}\n'
echo

lookup()
{
    for rev in "$@"; do
	printf "$rev: "
	hg id -nr $rev
    done
    true
}

tipnode=`hg id -ir tip`

echo 'should work with tag/branch/node/rev'
for r in tip default $tipnode 6; do
    lookup "$r^"
done
echo

echo 'some random lookups'
lookup "6^^" "6^^^" "6^^^^" "6^^^^^" "6^^^^^^" "6^1" "6^2" "6^^2" "6^1^2" "6^^3"
lookup "6~" "6~1" "6~2" "6~3" "6~4" "6~5" "6~42" "6~1^2" "6~1^2~2"
echo

echo 'with a tag "6^" pointing to rev 1'
hg tag -l -r 1 "6^"
lookup "6^" "6^1" "6~1" "6^^"
echo

echo 'with a tag "foo^bar" pointing to rev 2'
hg tag -l -r 2 "foo^bar"
lookup "foo^bar" "foo^bar^"