Branch Compare Panel — view files changed vs base branch

[Flamefork]

What are you proposing?

A panel that shows the list of files changed between the working tree and a user-selected base branch (or tag/commit), displayed as a tree view with collapsible folders.

Key features:

• Tree view of changed files (collapsible folders)
• Base ref selector — dropdown to pick branch/tag/commit to compare against
• Merge-base comparison — use git merge-base for accurate PR-style diff
• Click behavior — click opens diff of that file

Why does this matter?

When working on a feature branch, I need to see which files have changed compared to the base branch (e.g., main) before creating a PR — essentially a "PR preview" without leaving the editor.

Current state in Zed:

• Git Panel — shows files changed vs HEAD (staged/unstaged), not vs another branch
• git: branch diff — shows full inline diff vs default branch, but no navigable file list

What's missing is a quick way to see and navigate the list of changed files relative to the base branch.

Are there any examples or context?

VS Code extension Git Tree Compare provides this functionality:

Possible approach

Zed already has building blocks:

• BranchDiff in crates/project/src/git_store/branch_diff.rs computes TreeDiff with file list
• Git Panel already renders tree view of files
• DiffBase::Merge { base_ref } exists for merge-base comparison

Could be implemented as a new panel or as a mode/toggle in the existing Git Panel.

[raulk]

This would be super useful, along with the diff stat for each file, and maybe even the totals for the directory on hover.

You can kinda approximate this by collapsing all entries in the multibuffer, but you lose the tree hierarchy.

The outline panel retains the hierarchy, but it's quite clunky to use.