hgeditor

commit: make commit acquire store lock before processing for consistency

If acquisition of wlock waits for another "hg commit" process to
release it, dirstate will refer newly committed revision after
acquisition of wlock.

At that time, '00changelog.i' on the filesystem contains this new
revision, but in-memory 'repo.changelog' doesn't, if it is cached
without store lock (slock) before updating by another "hg commit".

This makes validating parents at re-loading 'repo.dirstate' from
'.hg/dirstate' replace such new revision with 'nullid'. Then,
'localrepository.commit()' creates "orphan" revision (see issue4368
for detail).

a01d3d32b53a makes 'commands.commit()' acquire both wlock and slock
before processing to avoid this issue at "hg commit".

But similar issue can occur even after a01d3d32b53a, if 3rd party
extension does:

  - refer 'repo.changelog' outside wlock scope, and
  - invoke 'repo.commit()' directly (instead of 'commands.commit()')

This patch makes 'commit()' acquire slock before processing, to refer
recent changelog at validating parents of 'repo.dirstate'.

#!/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 $?