view hgeditor @ 44905:f330d6117a5b

relnotes: advertize the possibility to use rust

I think the rust work may have been mentioned in the release notes,
but if so only in passing, and not as an invitation to try it out.

I think the next version is a decent time to do this, because the rust
doesn't come with performance regressions AFAIK, speeds up status
noticeably when it applies, which is the case for most invocations of
status, and doesn't have the undesirable restriction of regex around
empty patterns anymore.

I am cheating a bit, because I'm giving numbers for `hg status` in
mozilla-central, but they have one hgignore pattern that uses
lookaround, ".vscode/(?!extensions\.json|tasks\.json", which I took
out as it would cause a fallback to python when unknown files are
requested. But it seems that they could express their hgignore
differently if they were so inclined.

Not sure if there are limitation other than linux-only that I am
not thinking of but would be worth mentioning upfront, to avoid
disappointing users?

Differential Revision: https://phab.mercurial-scm.org/D8604

#!/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 $?