Bookmarks are Not Branches

Important

You learn that Bookmarks can point to multiple commits simultaneously.

Let’s dive into the oddities. You’re used to them by now.

• In Git, a branch is a label pointing to exactly 1 commit. A simple model¹.
• In Jujutsu, Bookmarks are labels that can point to multiple revisions.

This shouldn’t sound too weird; it’s consistent with what you know about conflicts:

• Changes pointing to 1 Tree are conflict-free.
• Changes pointing to multiple Trees have conflicts.

The same logic applies to Bookmarks. Normally, a Bookmark points to a single revision:

@  x   ◀─────── **foo**
│ ○  y
├─╯
○  q
◆  z

In this happy case, Git and Jujutsu are identical. You’ll see a log like this:

@  x  **foo**
│ ○  y
├─╯
○  q
◆  z

It may happen that you and a remote colleague move the same branch to irreconcilable positions. In that case, the Bookmark points to multiple revisions:

@  x   ◀────────┐
│               ├─ **foo**
│ ○  y   ◀──────┘
├─╯
○  q
◆  z

You have a Bookmark conflict. You must resolve it so the Bookmark points to just 1 revision. Jujutsu displays this as:

@  x  **foo??**
│ ○  y  **foo??**
├─╯
○  q
◆  z

The good news: the logic for resolving code conflicts applies here, and it’s even easier.

1. If it weren’t for the confusing name “branch”. In Git, a branch is both a reference to a commit and a sequence of commits diverging from the trunk. ↩