annotate hgeditor @ 990:5007e0bdeed2

Fix long-standing excessive file merges

Since switching to the multihead approach, we've been creating
excessive file-level merges where files are marked as merged with
their ancestors.

This explicitly checks at commit time whether the two parent versions
are linearly related, and if so, reduces the file check-in to a
non-merge. Then the file is compared against the remaining parent,
and, if equal, skips check-in of that file (as it's not changed).

Since we're not checking in all files that were different between
versions, we no longer need to mark so many files for merge. This
removes most of the 'm' state marking as well.

Finally, it is possible to do a tree-level merge with no file-level
changes. This will happen if one user changes file A and another
changes file B. Thus, if we have have two parents, we allow commit to
proceed even if there are no file-level changes.

#!/bin/sh
#
# This is an example of using HGEDITOR to automate the signing of
# commits and so on.

# change this to one to turn on GPG support
SIGN=0

# 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" 1 2 3 6 15 # HUP INT QUIT ABRT TERM

HGTMP="${TMPDIR-/tmp}/hgeditor.$RANDOM.$RANDOM.$RANDOM.$$"
(umask 077 && mkdir "$HGTMP") || {
    echo "Could not create temporary directory! Exiting." 1>&2
    exit 1
}

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

echo > "$HGTMP/msg"
if [ "$SIGN" == "1" ]; then
    MANIFEST=`grep '^HG: manifest hash' "$1" | cut -b 19-`
    echo -e "\nmanifest hash: $MANIFEST" >> "$HGTMP/msg"
fi
grep -vE '^(HG: manifest hash .*)?$' "$1" >> "$HGTMP/msg"

CHECKSUM=`md5sum "$HGTMP/msg"`
$EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $?
echo "$CHECKSUM" | md5sum -c >/dev/null 2>&1 && exit 13

if [ "$SIGN" == "1" ]; then
    {
        head -n 1 "$HGTMP/msg"
        echo
        grep -v "^HG:" "$HGTMP/msg" | gpg -t -a -u "${HGUSER}" --clearsign
    } > "$HGTMP/msg.gpg" && mv "$HGTMP/msg.gpg" "$1"
else
    mv "$HGTMP/msg" "$1"
fi

exit $?