git_graph: Add tree view for commit changed files

[chirivelli]

Self-Review Checklist:

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content is consistent with the UI/UX checklist
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

Summary:

• Added a toggleable tree view for changed files in the git graph commit details panel
• Reused shared ListItem rows and file icon folder rendering for changed-file entries
• Kept flat view available for status-sorted changed files

Tests:

• cargo check -p git_graph

Release Notes:

• Improved commit details changed-file lists with an optional tree view

[chirivelli]

here is a look the the feature

Screen.Recording.2026-06-01.at.11.16.51.AM.mov

[chirivelli]

@ChristopherBiscardi some QoL things your way!

[chirivelli]

my bad, fix for clippy issues, coming right up

[ChristopherBiscardi]

looks good, but has conflicts that need to be resolved. Probably due to a refactor that removed the git_graph crate: #57503

[chirivelli]

I'll try rebasing, but probably need to refactor a lot 😔

[dandv]

Hi @chirivelli — we independently built the same feature (mine is #58416, which closes #28104). Rather than have two competing PRs, I'd love to combine the best of both so the maintainers have one strong path to merge.

A few things yours does that I think are genuinely better:

• ListItem with indent_level/indent_step_size + the built-in disclosure toggle. This is the idiomatic primitive and sidesteps the manual indentation/icon-alignment work I did by hand.
• FileIcons::get_folder_icon(...) for theme-aware folder icons (with the IconName::Folder fallback), matching the Project Panel.

And a few things from mine that I think are worth folding in regardless of which PR lands:

• Tests. Mine has unit tests for the tree model — nesting, single-child directory compaction, a real-world nested layout, collapse/expand round-tripping, and empty input. This PR currently has none (the checklist's "Tests cover the new/changed behavior" is checked, but cargo check isn't a test). I'm happy to contribute these.
• Deleted files. Mine strikes through deleted files in both views, matching the Git Panel's treatment.
• A latent bug in the compaction helper. In compact_changed_file_directory_chain, the while loop's else arm does continue instead of break:

  while node.files.is_empty() && node.children.len() == 1 {
      let Some(child) = node.children.values().next() else {
          continue; // never advances the loop condition -> infinite loop if hit
      };

  In practice children.len() == 1 guarantees .next() is Some, so it doesn't trigger today — but it's a footgun (my version uses break). Worth fixing in whichever lands. (FWIW this continue is inherited from the git_panel original, so it may be worth fixing there too.)
• Default view mode. This PR defaults to Tree, which changes behavior for existing users — probably worth a maintainer's call.
• Error handling. The directory-toggle handlers use .ok() to discard the weak-entity update result; .rules prefers .log_err() so unexpected failures stay visible.

Happy to do the work here (or simply close mine) and follow @ChristopherBiscardi's lead.

[ChristopherBiscardi]

Thanks for rebasing @chirivelli

@dandv If you want to make additional PRs for tests or future-proofing the compaction helper and such feel free to.

[chirivelli]

@dandv great points!, feel free to fix those issues and add tests.
Thanks for working on this.