hgeditor

lfs: add git to the User-Agent header for blob transfers

As we were trying to transition off of the non production lfs-test-server for
further experimenting, one of the problems we ran into was interoperability.  A
coworker setup gitbucket[1] to act as the blob server, tested with git, and
passed it off to me.  But push failed with a message saying "abort: LFS server
returns invalid JSON:", and then proceeded to dump a huge HTML page to the
screen.  It turns out that it is assuming that git is the only thing that wants
to do a blob transfer, and everything else is a web browser wanting HTML.

It's only a single data point, but I suspect other things may be doing this too.
RFC7231 gives an example [2] of listing multiple products in decreasing order of
significance.  Since the standard provides for this, and since it works with the
one problematic server I found, I'm just enabling this by default for a better
UX.

There's nothing significant about the version of git chosen, other than it is
the current version.

[1] https://github.com/gitbucket/gitbucket/
[2] https://tools.ietf.org/html/rfc7231#page-46

#!/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 $?