Using Jujutsu¶

After playing around with Jujutsu (aka jj) for a while I have to say I really like it!

If I had to sum up the difference between git and jj I would say that it’s like the difference imperative and declarative programming. In git I have to spell out every operation it has to perform to get the commit graph I want - over and over again as I make changes. While in jj, I tell it once what I want the commit graph to look like and I can make changes throughout history and it will maintain that graph for me automatically in the background.

Command Reference¶

For now I want to use git and jj side by side:

$ jj git init --colocate

Branches occur when you have multiple changes that share a single parent:

$ jj new parent -m "Commit one"
$ jj new parent -m "Commit two"

To merge branches, create a new change with multiple parents:

$ jj new <rev1> <rev2> [... <revN>]

You only really need name a branch (aka bookmark) when you want to push your changes somewhere:

$ jj bookmark set -r <rev> <name>
$ jj git push -b <name> --remote <remote> --allow-new

To push again after you’ve made additional changes:

$ jj bookmark set -r <rev> <name>  # Unlike git branches, bookmarks don't move each time you commit
$ jj git push -b <name> --remote <remote>

User Config¶

Here lies my user config for jj

As with git, you need to set a name and email for your commits

jj/config.toml

"$schema" = "https://jj-vcs.github.io/jj/latest/config-schema.json"

user.name = "Alex Carney"
user.email = "alcarneyme@gmail.com"

Use emacs as my editor

jj/config.toml

ui.editor = "emacsclient"

By default, running jj with no arguments shows you the log, I prefer this to be the status command

jj/config.toml

ui.default-command = "status"

For compatibilty with other tools, it’s best to render diffs and conflicts as git would

jj/config.toml

ui.conflict-marker-style = "git"
ui.diff-formatter = ":git"

Repo Config¶

Tip

Edit the configuration for the current repo by running:

jj config edit --repo

Considering how easy it is to rewrite history in jj it’s easy to imagine accidentally creating a mess for yourself. So, by default jj will mark changes belonging to the revset trunk() as immutable.

[revset-aliases]
"trunk()" = "develop@upstream"