Version control systems

Sapling and Jujutsu are version control systems that can work in a Git repository: sl and jj read and write .git/, and Git commands still work. So git-splice can run next to them, within limits. The pages run each one on the same library and monorepo as git submodule and git subtree.

• Sapling: sl subtree imports a repository into a folder and merges its changes, recording the sync point in each commit's metadata, and sends nothing back.
• Jujutsu: jj has nothing built in for a library in a folder yet, and doesn't see inside submodules. A splice is files to jj, but git-splice needs Git back on a branch first.

	Sapling	Jujutsu
In a Git repository	.git/sl/ next to Git's data; sl clone makes a repository without it	colocated: .jj/ next to .git/
Library in a folder	sl subtree import and merge	none released
Sync point recorded	in each commit's metadata, an extra header to Git	none
Changes back to the library	a patch by hand	none
Git's HEAD	on the branch after sl commit, detached after sl goto	detached at @- after jj commit or jj new
git-splice next to it	works on a branch; sl amend leaves Git's index behind	works after jj bookmark set and git checkout
What git-splice could do	Sapling	Jujutsu