hgeditor

rebase: allow for rebasing descendants onto ancestors on different named branches

So far we've been denying rebasing descendants onto ancestors, but there are
situations in which this kind of operation makes perfect sense to me.

Let's say we have made a commit (or more), that belongs to branch 'dev', on
top of the named branch 'stable':

... a (stable) - b (dev)

but then we realize that b should belong to branch 'stable'.
In these cases a rebase means: "move these csets from named branch A to named
branch B" and there isn't a valid reason to deny it.

This patch basically doesn't block it, if source and destination are
on different named branches.
The old behaviour still applies for rebases across the same named branch.

Can you think of any tricky corner cases in which this new behaviour could
lead to problems? (I bet there are tons of them...)

By the way, I created a brand new .t because I feel there should be more
tests I can't think of at the moment.

#!/bin/sh
#
# This is an example of using HGEDITOR to create of diff to review the
# changes while commiting.

# If you want to pass your favourite editor some other parameters
# only for Mercurial, modify this:
case "${EDITOR}" in
    "")
        EDITOR="vi"
        ;;
    emacs)
        EDITOR="$EDITOR -nw"
        ;;
    gvim|vim)
        EDITOR="$EDITOR -f -o"
        ;;
esac


HGTMP=""
cleanup_exit() {
    rm -rf "$HGTMP"
}

# Remove temporary files even if we get interrupted
trap "cleanup_exit" 0 # normal exit
trap "exit 255" HUP INT QUIT ABRT TERM

HGTMP=$(mktemp -d ${TMPDIR-/tmp}/hgeditor.XXXXXX)
[ x$HGTMP != x -a -d $HGTMP ] || {
  echo "Could not create temporary directory! Exiting." 1>&2
  exit 1
}

(
    grep '^HG: changed' "$1" | cut -b 13- | while read changed; do
        "$HG" diff "$changed" >> "$HGTMP/diff"
    done
)

cat "$1" > "$HGTMP/msg"

MD5=$(which md5sum 2>/dev/null) || \
    MD5=$(which md5 2>/dev/null)
[ -x "${MD5}" ] && CHECKSUM=`${MD5} "$HGTMP/msg"`
if [ -s "$HGTMP/diff" ]; then
    $EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $?
else
    $EDITOR "$HGTMP/msg" || exit $?
fi
[ -x "${MD5}" ] && (echo "$CHECKSUM" | ${MD5} -c >/dev/null 2>&1 && exit 13)

mv "$HGTMP/msg" "$1"

exit $?