Add support for for git-subtree

This lib allows you to merge separate git repos into a single repo, and
push changes back to the separate repos.

See https://github.com/apenwarr/git-subtree for the git-subtree command.

diff --git a/lib/git-subtree b/lib/git-subtree
new file mode 100644 (file)
index 0000000..45b048e
--- /dev/null
+++ b/lib/git-subtree
@@ -0,0 +1,40 @@
+# Add support for Avery Pennarun's git-subtree
+#
+# Example:
+#
+# [repo]
+# checkout = git clone git.example.org:repo.git
+#
+# [repo/lib]
+# git_subtree_test = true
+# checkout = git subtree add --prefix=lib git.example.org:lib.git master
+# update = git_subtree_update --prefix=lib git.example.org:lib.git master
+# push = git_subtree_push --prefix=lib git.example.org:lib.git master
+
+lib =
+       git_get_toplevel() {
+               local toplevel
+               toplevel="$(git rev-parse --show-toplevel)" || true
+               if [ -z "$toplevel" ]; then
+                       error "git toplevel is not set"
+               fi
+               toplevel="${toplevel%%/}/"
+               if [ ! -d "$toplevel" ]; then
+                       error "git toplevel $toplevel does not exist"
+               fi
+               echo "$toplevel"
+       }
+       git_subtree_update() {
+               cd "$(git_get_toplevel)"
+               git subtree pull "$@"
+       }
+       git_subtree_push() {
+               cd "$(git_get_toplevel)"
+               git subtree push "$@"
+       }
+
+git_subtree_status = git status .
+git_subtree_commit = git add . && git commit "$@" && git_subtree_push
+git_subtree_record = git add . && git commit "$@"
+git_subtree_diff = git diff .
+git_subtree_log = git log .