Worktree paths in git panel, take 2 (#26047)

Modified version of #25950. We still use worktree paths, but repo paths
with a status that lie outside the worktree are not excluded; instead,
we relativize them by adding `..`. This makes the list in the git panel
match what you'd get from running `git status` (with the repo's worktree
root as the working directory).

- [x] Implement + test new unrelativization logic
- [x] ~~When collecting repositories, dedup by .git abs path, so
worktrees can share a repo at the project level~~ dedup repos at the
repository selector layer, with repos coming from larger worktrees being
preferred
- [x] Open single-file worktree with diff when activating a path not in
the worktree

Release Notes:

- N/A

crates/git_ui/src/repository_selector.rs

@@ -3,7 +3,10 @@ use gpui::{
 };
 use itertools::Itertools;
 use picker::{Picker, PickerDelegate};
-use project::{git::Repository, Project};
+use project::{
+    git::{GitStore, Repository},
+    Project,
+};
 use std::sync::Arc;
 use ui::{prelude::*, ListItem, ListItemSpacing};
 
@@ -17,12 +20,14 @@ impl RepositorySelector {
         window: &mut Window,
         cx: &mut Context<Self>,
     ) -> Self {
+        let git_store = project_handle.read(cx).git_store().clone();
+        let repository_entries = git_store.update(cx, |git_store, cx| {
+            filtered_repository_entries(git_store, cx)
+        });
         let project = project_handle.read(cx);
-        let git_store = project.git_store().clone();
-        let all_repositories = git_store.read(cx).all_repositories();
-        let filtered_repositories = all_repositories.clone();
+        let filtered_repositories = repository_entries.clone();
 
-        let widest_item_ix = all_repositories.iter().position_max_by(|a, b| {
+        let widest_item_ix = repository_entries.iter().position_max_by(|a, b| {
             a.read(cx)
                 .display_name(project, cx)
                 .len()
@@ -32,7 +37,7 @@ impl RepositorySelector {
         let delegate = RepositorySelectorDelegate {
             project: project_handle.downgrade(),
             repository_selector: cx.entity().downgrade(),
-            repository_entries: all_repositories.clone(),
+            repository_entries,
             filtered_repositories,
             selected_index: 0,
         };
@@ -47,6 +52,35 @@ impl RepositorySelector {
     }
 }
 
+pub(crate) fn filtered_repository_entries(
+    git_store: &GitStore,
+    cx: &App,
+) -> Vec<Entity<Repository>> {
+    let mut repository_entries = git_store.all_repositories();
+    repository_entries.sort_by_key(|repo| {
+        let repo = repo.read(cx);
+        (
+            repo.dot_git_abs_path.clone(),
+            repo.worktree_abs_path.clone(),
+        )
+    });
+    // Remove any entry that comes from a single file worktree and represents a repository that is also represented by a non-single-file worktree.
+    repository_entries
+        .chunk_by(|a, b| a.read(cx).dot_git_abs_path == b.read(cx).dot_git_abs_path)
+        .flat_map(|chunk| {
+            let has_non_single_file_worktree = chunk
+                .iter()
+                .any(|repo| !repo.read(cx).is_from_single_file_worktree);
+            chunk
+                .iter()
+                .filter(move |repo| {
+                    !repo.read(cx).is_from_single_file_worktree || !has_non_single_file_worktree
+                })
+                .cloned()
+        })
+        .collect()
+}
+
 impl EventEmitter<DismissEvent> for RepositorySelector {}
 
 impl Focusable for RepositorySelector {