view hgeditor @ 27414:6602a7b9deec

histedit: delete to drop

The default behaviour to forbid this makes a lot of sense for novice users
because it's safeguarding them from dangerous behavior but making it
configurable will be apprieciated by power users in at least one big
organization.

It allows an user to look an histedit rules from declarative perspective and
make the rules reflect the state after histedit.  If we can move lines t move
commits why can't we drop lines to drop commits?

Let's put this behind config knob and inform users about this feature the very
moment they are trying to use it so they can choose desired behaviour.

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

# 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 $?