#
# git-subtree.sh: split/join git repositories in subdirectories of this one
#
-# Copyright (
c) 2009 Avery Pennarun <apenwarr@gmail.com>
+# Copyright (
C) 2009 Avery Pennarun <apenwarr@gmail.com>
#
+if [ $# -eq 0 ]; then
+ set -- -h
+fi
OPTS_SPEC="\
-git subtree split <revisions> -- <subdir>
-git subtree merge
-
-git subtree does foo and bar!
+git subtree add --prefix=<prefix> <commit>
+git subtree split [options...] --prefix=<prefix> <commit...>
+git subtree merge --prefix=<prefix> <commit>
+git subtree pull --prefix=<prefix> <repository> <refspec...>
--
-h,help show the help
-q quiet
-v verbose
+h,help show the help
+q quiet
+prefix= the name of the subdir to split out
+ options for 'split'
+onto= try connecting new tree to an existing one
+rejoin merge the new branch back into HEAD
+ignore-joins ignore prior --rejoin commits
"
eval $(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)
. git-sh-setup
quiet=
command=
+onto=
+rejoin=
+ignore_joins=
debug()
{
shift
case "$opt" in
-q) quiet=1 ;;
+ --prefix) prefix="$1"; shift ;;
+ --no-prefix) prefix= ;;
+ --onto) onto="$1"; shift ;;
+ --no-onto) onto= ;;
+ --rejoin) rejoin=1 ;;
+ --no-rejoin) rejoin= ;;
+ --ignore-joins) ignore_joins=1 ;;
+ --no-ignore-joins) ignore_joins= ;;
--) break ;;
esac
done
command="$1"
shift
case "$command" in
- split|merge) ;;
+ add|merge|pull) default= ;;
+ split) default="--default HEAD" ;;
*) die "Unknown command '$command'" ;;
esac
-revs=$(git rev-parse --default HEAD --revs-only "$@") || exit $?
-dirs="$(git rev-parse --sq --no-revs --no-flags "$@")" || exit $?
+if [ -z "$prefix" ]; then
+ die "You must provide the --prefix option."
+fi
+dir="$prefix"
-#echo "dirs is {$dirs}"
-eval $(echo set -- $dirs)
-if [ "$#" -ne 1 ]; then
- die "Must provide exactly one subtree dir (got $#)"
+if [ "$command" != "pull" ]; then
+ revs=$(git rev-parse $default --revs-only "$@") || exit $?
+ dirs="$(git rev-parse --no-revs --no-flags "$@")" || exit $?
+ if [ -n "$dirs" ]; then
+ die "Error: Use --prefix instead of bare filenames."
+ fi
fi
-dir="$1"
debug "command: {$command}"
debug "quiet: {$quiet}"
debug "revs: {$revs}"
debug "dir: {$dir}"
+debug "opts: {$*}"
+debug
cache_setup()
{
{
oldrev="$1"
newrev="$2"
- if [ "$oldrev" != "latest" -a -e "$cachedir/$oldrev" ]; then
+ if [ "$oldrev" != "latest_old" \
+ -a "$oldrev" != "latest_new" \
+ -a -e "$cachedir/$oldrev" ]; then
die "cache for $oldrev already exists!"
fi
echo "$newrev" >"$cachedir/$oldrev"
}
+# if a commit doesn't have a parent, this might not work. But we only want
+# to remove the parent from the rev-list, and since it doesn't exist, it won't
+# be there anyway, so do nothing in that case.
+try_remove_previous()
+{
+ if git rev-parse "$1^" >/dev/null 2>&1; then
+ echo "^$1^"
+ fi
+}
+
+find_existing_splits()
+{
+ debug "Looking for prior splits..."
+ dir="$1"
+ revs="$2"
+ git log --grep="^git-subtree-dir: $dir\$" \
+ --pretty=format:'%s%n%n%b%nEND' "$revs" |
+ while read a b junk; do
+ case "$a" in
+ git-subtree-mainline:) main="$b" ;;
+ git-subtree-split:) sub="$b" ;;
+ *)
+ if [ -n "$main" -a -n "$sub" ]; then
+ debug " Prior: $main -> $sub"
+ cache_set $main $sub
+ try_remove_previous "$main"
+ try_remove_previous "$sub"
+ main=
+ sub=
+ fi
+ ;;
+ esac
+ done
+}
+
copy_commit()
{
# We're doing to set some environment vars here, so
read GIT_COMMITTER_NAME
read GIT_COMMITTER_EMAIL
read GIT_COMMITTER_DATE
- export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE
- export GIT_COMMITTER_NAME GIT_COMMITTER_EMAIL GIT_COMMITTER_DATE
+ export GIT_AUTHOR_NAME \
+ GIT_AUTHOR_EMAIL \
+ GIT_AUTHOR_DATE \
+ GIT_COMMITTER_NAME \
+ GIT_COMMITTER_EMAIL \
+ GIT_COMMITTER_DATE
+ (echo -n '*'; cat ) | # FIXME
git commit-tree "$2" $3 # reads the rest of stdin
) || die "Can't copy commit $1"
}
+add_msg()
+{
+ dir="$1"
+ latest_old="$2"
+ latest_new="$3"
+ cat <<-EOF
+ Add '$dir/' from commit '$latest_new'
+
+ git-subtree-dir: $dir
+ git-subtree-mainline: $latest_old
+ git-subtree-split: $latest_new
+ EOF
+}
+
+merge_msg()
+{
+ dir="$1"
+ latest_old="$2"
+ latest_new="$3"
+ cat <<-EOF
+ Split '$dir/' into commit '$latest_new'
+
+ git-subtree-dir: $dir
+ git-subtree-mainline: $latest_old
+ git-subtree-split: $latest_new
+ EOF
+}
+
+toptree_for_commit()
+{
+ commit="$1"
+ git log -1 --pretty=format:'%T' "$commit" -- || exit $?
+}
+
+subtree_for_commit()
+{
+ commit="$1"
+ dir="$2"
+ git ls-tree "$commit" -- "$dir" |
+ while read mode type tree name; do
+ assert [ "$name" = "$dir" ]
+ echo $tree
+ break
+ done
+}
+
+tree_changed()
+{
+ tree=$1
+ shift
+ if [ $# -ne 1 ]; then
+ return 0 # weird parents, consider it changed
+ else
+ ptree=$(toptree_for_commit $1)
+ if [ "$ptree" != "$tree" ]; then
+ return 0 # changed
+ else
+ return 1 # not changed
+ fi
+ fi
+}
+
+copy_or_skip()
+{
+ rev="$1"
+ tree="$2"
+ newparents="$3"
+ assert [ -n "$tree" ]
+
+ identical=
+ p=
+ for parent in $newparents; do
+ ptree=$(toptree_for_commit $parent) || exit $?
+ if [ "$ptree" = "$tree" ]; then
+ # an identical parent could be used in place of this rev.
+ identical="$parent"
+ fi
+ if [ -n "$ptree" ]; then
+ parentmatch="$parentmatch$parent"
+ p="$p -p $parent"
+ fi
+ done
+
+ if [ -n "$identical" -a "$parentmatch" = "$identical" ]; then
+ echo $identical
+ else
+ copy_commit $rev $tree "$p" || exit $?
+ fi
+}
+
+ensure_clean()
+{
+ if ! git diff-index HEAD --exit-code --quiet; then
+ die "Working tree has modifications. Cannot add."
+ fi
+ if ! git diff-index --cached HEAD --exit-code --quiet; then
+ die "Index has modifications. Cannot add."
+ fi
+}
+
+cmd_add()
+{
+ if [ -e "$dir" ]; then
+ die "'$dir' already exists. Cannot add."
+ fi
+ ensure_clean
+
+ set -- $revs
+ if [ $# -ne 1 ]; then
+ die "You must provide exactly one revision. Got: '$revs'"
+ fi
+ rev="$1"
+
+ debug "Adding $dir as '$rev'..."
+ git read-tree --prefix="$dir" $rev || exit $?
+ git checkout "$dir" || exit $?
+ tree=$(git write-tree) || exit $?
+
+ headrev=$(git rev-parse HEAD) || exit $?
+ if [ -n "$headrev" -a "$headrev" != "$rev" ]; then
+ headp="-p $headrev"
+ else
+ headp=
+ fi
+ commit=$(add_msg "$dir" "$headrev" "$rev" |
+ git commit-tree $tree $headp -p "$rev") || exit $?
+ git reset "$commit" || exit $?
+}
+
cmd_split()
{
debug "Splitting $dir..."
cache_setup || exit $?
- git rev-list --reverse --parents $revs -- "$dir" |
+ if [ -n "$onto" ]; then
+ debug "Reading history for --onto=$onto..."
+ git rev-list $onto |
+ while read rev; do
+ # the 'onto' history is already just the subdir, so
+ # any parent we find there can be used verbatim
+ debug " cache: $rev"
+ cache_set $rev $rev
+ done
+ fi
+
+ if [ -n "$ignore_joins" ]; then
+ unrevs=
+ else
+ unrevs="$(find_existing_splits "$dir" "$revs")"
+ fi
+
+ # We can't restrict rev-list to only "$dir" here, because that leaves out
+ # critical information about commit parents.
+ debug "git rev-list --reverse --parents $revs $unrevs"
+ git rev-list --reverse --parents $revs $unrevs |
while read rev parents; do
- newparents=$(cache_get $parents)
debug
- debug "Processing commit: $rev / $newparents"
+ debug "Processing commit: $rev"
+ exists=$(cache_get $rev)
+ if [ -n "$exists" ]; then
+ debug " prior: $exists"
+ continue
+ fi
+ debug " parents: $parents"
+ newparents=$(cache_get $parents)
+ debug " newparents: $newparents"
- git ls-tree $rev -- "$dir" |
- while read mode type tree name; do
- assert [ "$name" = "$dir" ]
- debug " tree is: $tree"
- p=""
- for parent in $newparents; do
- p="$p -p $parent"
- done
-
- newrev=$(copy_commit $rev $tree "$p") || exit $?
- debug " newrev is: $newrev"
- cache_set $rev $newrev
- cache_set latest $newrev
- done || exit $?
+ tree=$(subtree_for_commit $rev "$dir")
+ debug " tree is: $tree"
+ [ -z $tree ] && continue
+
+ newrev=$(copy_or_skip "$rev" "$tree" "$newparents") || exit $?
+ debug " newrev is: $newrev"
+ cache_set $rev $newrev
+ cache_set latest_new $newrev
+ cache_set latest_old $rev
done || exit $?
- latest=$(cache_get latest)
- if [ -z "$latest" ]; then
+ latest_new=$(cache_get latest_new)
+ if [ -z "$latest_new" ]; then
die "No new revisions were found"
fi
- echo $latest
+
+ if [ -n "$rejoin" ]; then
+ debug "Merging split branch into HEAD..."
+ latest_old=$(cache_get latest_old)
+ git merge -s ours \
+ -m "$(merge_msg $dir $latest_old $latest_new)" \
+ $latest_new >&2
+ fi
+ echo $latest_new
exit 0
}
cmd_merge()
{
- die "merge command not implemented yet"
+ ensure_clean
+
+ set -- $revs
+ if [ $# -ne 1 ]; then
+ die "You must provide exactly one revision. Got: '$revs'"
+ fi
+ rev="$1"
+
+ git merge -s subtree $rev
+}
+
+cmd_pull()
+{
+ ensure_clean
+ set -x
+ git pull -s subtree "$@"
}
-"cmd_$command"
+"cmd_$command" "$@"