assistant2: Fix file context picker (#22163)

This PR fixes an issue with the Assistant2 file context picker where
files weren't being attached properly.

We needed to retrieve the files from the worktree without the worktree
root name in the file path.

Release Notes:

- N/A

---------

Co-authored-by: Max <max@zed.dev>

crates/assistant2/src/context_picker/file_context_picker.rs

@@ -1,6 +1,6 @@
 use std::fmt::Write as _;
 use std::ops::RangeInclusive;
-use std::path::{Path, PathBuf};
+use std::path::Path;
 use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
 
@@ -79,44 +79,37 @@ impl FileContextPickerDelegate {
         if query.is_empty() {
             let workspace = workspace.read(cx);
             let project = workspace.project().read(cx);
-            let entries = workspace.recent_navigation_history(Some(10), cx);
-
-            let entries = entries
+            let recent_matches = workspace
+                .recent_navigation_history(Some(10), cx)
                 .into_iter()
-                .map(|entries| entries.0)
-                .chain(project.worktrees(cx).flat_map(|worktree| {
-                    let worktree = worktree.read(cx);
-                    let id = worktree.id();
-                    worktree
-                        .child_entries(Path::new(""))
-                        .filter(|entry| entry.kind.is_file())
-                        .map(move |entry| project::ProjectPath {
-                            worktree_id: id,
-                            path: entry.path.clone(),
-                        })
-                }))
-                .collect::<Vec<_>>();
-
-            let path_prefix: Arc<str> = Arc::default();
-            Task::ready(
-                entries
-                    .into_iter()
-                    .filter_map(|entry| {
-                        let worktree = project.worktree_for_id(entry.worktree_id, cx)?;
-                        let mut full_path = PathBuf::from(worktree.read(cx).root_name());
-                        full_path.push(&entry.path);
-                        Some(PathMatch {
-                            score: 0.,
-                            positions: Vec::new(),
-                            worktree_id: entry.worktree_id.to_usize(),
-                            path: full_path.into(),
-                            path_prefix: path_prefix.clone(),
-                            distance_to_relative_ancestor: 0,
-                            is_dir: false,
-                        })
+                .filter_map(|(project_path, _)| {
+                    let worktree = project.worktree_for_id(project_path.worktree_id, cx)?;
+                    Some(PathMatch {
+                        score: 0.,
+                        positions: Vec::new(),
+                        worktree_id: project_path.worktree_id.to_usize(),
+                        path: project_path.path,
+                        path_prefix: worktree.read(cx).root_name().into(),
+                        distance_to_relative_ancestor: 0,
+                        is_dir: false,
                     })
-                    .collect(),
-            )
+                });
+
+            let file_matches = project.worktrees(cx).flat_map(|worktree| {
+                let worktree = worktree.read(cx);
+                let path_prefix: Arc<str> = worktree.root_name().into();
+                worktree.files(true, 0).map(move |entry| PathMatch {
+                    score: 0.,
+                    positions: Vec::new(),
+                    worktree_id: worktree.id().to_usize(),
+                    path: entry.path.clone(),
+                    path_prefix: path_prefix.clone(),
+                    distance_to_relative_ancestor: 0,
+                    is_dir: false,
+                })
+            });
+
+            Task::ready(recent_matches.chain(file_matches).collect())
         } else {
             let worktrees = workspace.read(cx).visible_worktrees(cx).collect::<Vec<_>>();
             let candidate_sets = worktrees
@@ -253,16 +246,30 @@ impl PickerDelegate for FileContextPickerDelegate {
         _cx: &mut ViewContext<Picker<Self>>,
     ) -> Option<Self::ListItem> {
         let path_match = &self.matches[ix];
-        let file_name = path_match
-            .path
-            .file_name()
-            .unwrap_or_default()
-            .to_string_lossy()
-            .to_string();
-        let directory = path_match
-            .path
-            .parent()
-            .map(|directory| format!("{}/", directory.to_string_lossy()));
+
+        let (file_name, directory) = if path_match.path.as_ref() == Path::new("") {
+            (SharedString::from(path_match.path_prefix.clone()), None)
+        } else {
+            let file_name = path_match
+                .path
+                .file_name()
+                .unwrap_or_default()
+                .to_string_lossy()
+                .to_string()
+                .into();
+
+            let mut directory = format!("{}/", path_match.path_prefix);
+            if let Some(parent) = path_match
+                .path
+                .parent()
+                .filter(|parent| parent != &Path::new(""))
+            {
+                directory.push_str(&parent.to_string_lossy());
+                directory.push('/');
+            }
+
+            (file_name, Some(directory))
+        };
 
         Some(
             ListItem::new(ix).inset(true).toggle_state(selected).child(