mercurial: create a monorepository from repository with subrepositories

subrepos-flatten.sh

#!/bin/sh

set -eu

HG="hg --config subrepos.allowed=True"

if [ $# -ne 2 ] ; then
    echo "usage: $0 source-repository destdir"
fi

SDIR=`readlink -f "${1}"`
DDIR="${2}"

# ensure SDIR is a mercurial repository with subrepositories
if [ ! -d "${SDIR}/.hg" -a -e "${SDIR}/.hgsub" ]; then
    echo "error: invalid source-repository: ${SDIR}"
    exit 1
fi

# ensure DDIR is not existent
if [ -d "${DDIR}" ]; then
    echo "error: destdir already exists: ${DDIR}"
    exit 1
fi

# create destdir
mkdir -p "${DDIR}"
DDIR=`readlink -f "${DDIR}"`

cd "${DDIR}" && ${HG} init


# PREPARE PHASE

# for each branches of SDIR
cd "${SDIR}" && ${HG} branches -T '{branch} {node}\n' | while read branch_name branch_id ; do

    # update to the branch
    echo "[+] updating to branch '${branch_name}' id=${branch_id}"
    cd "${SDIR}" && ${HG} update -C -r "${branch_id}"

    # for each subrepositories
    sed -ne 's/^\([^ ]*\) =.*/\1/p' <"${SDIR}/.hgsub" | while read subdir ; do
	echo "[+] prepare merge: ${subdir}"
	cd "${SDIR}/${subdir}"

	# purpose is to make changes which will avoid merge conflicts
	
	# tags rename: XXX -> ${subdir}-XXX
	if [ -r ".hgtags" ]; then
	    sed -i -e "s, , ${subdir}-," ".hgtags"
	fi

	# create a subdirectory
	# rename is done in 2 steps
	RENAME=`mktemp -d rename.XXXXXXXXXX` || exit 1

	# rename step1
	${HG} rename * "${RENAME}"
	for f in .drone.yml .flake8 .bower_allow_root.sh ; do
	    [ -e "${f}" ] && ${HG} rename "${f}" "${RENAME}"
	done

	# rename step2
	${HG} rename "${RENAME}" "${subdir}"

	# commit changes
	${HG} commit -m "subrepos-flatten: prepare merge: ${branch_name} (${branch_id}) - ${subdir}"


	# merge subdir inside DDIR
	echo "[+] merging: ${subdir}"
	cd ${DDIR} && ${HG} pull -f "${SDIR}/${subdir}"
    done

    # commit changes at toplevel
    #cd "${SDIR}" && ${HG} commit -m "subrepos-flatten: prepare merge: ${branch_name} (${branch_id})"
done

# MERGE PHASE

# for each branches of SDIR
cd "${SDIR}" && ${HG} branches -T '{branch}\n' | while read branch_name ; do

	# update to the branch
	echo "[+] updating to branch '${branch_name}'"
	cd "${DDIR}" && ${HG} update -C -r "${branch_name}"
	
	# merge heads while not only one heads per branch
	while [ $(hg heads -T '{node}\n' . | wc -l) -ne 1 ]; do

	    # update to commit0
	    hg heads -T '{node}\n' . | head -1 | xargs ${HG} update -C -r
	    
	    # merge with commitN
	    if ! hg heads -T '{node}\n' . | tail -1 | xargs ${HG} merge -r ; then
		
		# merge tags (keeping both)
		if [ -f .hgtags ]; then
		    sed -i \
			-e '/^<<<<<<< working copy/d' \
			-e '/^=======/d' \
			-e '/^>>>>>>> merge rev/d' \
			.hgtags
		    
		    hg resolv --mark .hgtags
		fi
	    fi
	    
	    hg commit -m "subrepos-flatten: merge: ${branch_name}"
	done
    done