hgmerge

cleanup of revlog.group when repository is local

revlog.group cached every chunk from the revlog, the behaviour was
needed to minimize the roundtrip with old-http.

The patch export the information that the repository is local or not
from the repository object down to the revlog.
Then it uses the workaround for old-http only if the repository is non-local.

The memory used server side when pulling goes down to less than 30Mo maximum
whereas without the patch more than 160Mo was used when cloning the linux kernel
repository.
The time used by cloning is roughly the same (although some caching could be
implemented if needed):
before
110.25user 20.90system 2:52.00elapsed 76%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+708707minor)pagefaults 0swaps
after
112.85user 22.98system 2:50.66elapsed 79%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+862862minor)pagefaults 0swaps

#!/bin/sh
#
# hgmerge - default merge helper for Mercurial
#
# This tries to find a way to do three-way merge on the current system.
# The result ought to end up in $1.

set -e # bail out quickly on failure

LOCAL="$1"
BASE="$2"
OTHER="$3"

if [ -z "$EDITOR" ]; then
    EDITOR="vi"
fi

# find decent versions of our utilities, insisting on the GNU versions where we
# need to
DIFF3=gdiff3
DIFF=gdiff
PATCH=gpatch

type $DIFF3 >/dev/null 2>&1 || DIFF3=diff3
type $DIFF  >/dev/null 2>&1 || DIFF=diff
type $PATCH  >/dev/null 2>&1 || PATCH=patch
$DIFF3 --version >/dev/null 2>&1 || DIFF3=

# Back up our file
cp "$LOCAL" "$LOCAL.orig"

# Attempt to do a non-interactive merge
if type merge > /dev/null 2>&1; then
    merge "$LOCAL" "$BASE" "$OTHER" 2> /dev/null && exit 0
    cp "$LOCAL.orig" "$LOCAL"
elif [ -n "$DIFF3" ]; then
    echo $DIFF3 -m "$LOCAL.orig" "$BASE" "$OTHER"
    $DIFF3 -m "$LOCAL.orig" "$BASE" "$OTHER" > "$LOCAL" && exit 0
    if [ $? -eq 2 ]; then
        echo "$DIFF3 failed! Exiting." 1>&2
        cp "$LOCAL.orig" "$LOCAL"
        exit 1
    fi
    cp "$LOCAL.orig" "$LOCAL"
fi

if [ -n "$DISPLAY" ]; then
    # try using kdiff3, which is fairly nice
    if type kdiff3 > /dev/null 2>&1; then
	kdiff3 --auto "$BASE" "$LOCAL" "$OTHER" -o "$LOCAL" || exit 1
	exit 0
    fi

    # try using tkdiff, which is a bit less sophisticated
    if type tkdiff > /dev/null 2>&1; then
	tkdiff "$LOCAL" "$OTHER" -a "$BASE" -o "$LOCAL" || exit 1
	exit 0
    fi
fi

# Attempt to do a merge with $EDITOR
if type merge > /dev/null 2>&1; then
    echo "conflicts detected in $LOCAL"
    merge "$LOCAL" "$BASE" "$OTHER" 2>/dev/null || $EDITOR "$LOCAL"
    exit 0
fi

if [ -n "$DIFF3" ]; then
    echo "conflicts detected in $LOCAL"
    $DIFF3 -m "$LOCAL.orig" "$BASE" "$OTHER" > "$LOCAL" || {
        case $? in
            1)
                $EDITOR "$LOCAL" ;;
            2)  echo "$DIFF3 failed! Exiting." 1>&2
                cp "$LOCAL.orig" "$LOCAL"
                exit 1 ;;
        esac
        exit 0
    }
fi

HGTMP=""
cleanup_exit() {
    rm -rf "$HGTMP"
}

# attempt to manually merge with diff and patch
if [ -n "$DIFF" -a -n "$PATCH" ]; then
    # Remove temporary files even if we get interrupted
    trap "cleanup_exit" 0 # normal exit
    trap "exit 1" 1 2 3 6 15 # HUP INT QUIT ABRT TERM

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

    $DIFF -u "$BASE" "$OTHER" > "$HGTMP/diff" || :
    if $PATCH "$LOCAL" < "$HGTMP/diff"; then
	exit 0
    else
	# If rejects are empty after using the editor, merge was ok
	$EDITOR "$LOCAL" "$LOCAL.rej" && test -s "$LOCAL.rej" || exit 0
    fi
    exit 1
fi

echo "hgmerge: unable to find merge, tkdiff, kdiff3, or diff+patch!"
exit 1