Add support for the "..." entry in file_scan_exclusions (#62769)

## Objective

`file_scan_exclusions` replaces the defaults instead of adding to them,
so excluding one extra directory means restating all eleven default
globs and never picking up defaults added in later Zed releases.

## Solution

`file_scan_exclusions` now accepts the `"..."` entry, which expands to
the value it overrides, so `["**/node_modules", "..."]` adds to the
inherited globs instead of replacing them. Entries listed by name keep
their position, and leaving `"..."` out still replaces the list
outright, so existing settings behave exactly as they do today.

## Testing

- Four unit tests in `crates/settings_content/src/project.rs` cover
splicing versus replacing, accumulation across successive layers, and
edge cases: a repeated `"..."`, an empty list clearing the value, and a
bare `["..."]` leaving it unchanged.
- To check by hand: set `"file_scan_exclusions": ["**/node_modules",
"..."]` in user settings and confirm `node_modules` disappears from the
project panel and file finder while `.git` and `.DS_Store` stay
excluded. Remove `"..."` and confirm only `node_modules` is excluded.
Repeat in a project's `.zed/settings.json` to confirm it splices the
resolved user settings rather than the defaults.
- Tested on macOS. This is platform-independent settings-merge logic
with no OS-specific code paths, so I did not test Linux or Windows.

## Self-Review Checklist:

- [x] I’ve reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed’s UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

---

Release Notes:

- Added support for the `"..."` entry in `file_scan_exclusions`. Custom
exclusions can now extend the defaults instead of replacing them.

crates/agent/src/tools/grep_tool.rs

@@ -398,7 +398,7 @@ mod tests {
     use gpui::{TestAppContext, UpdateGlobal};
     use project::{FakeFs, Project};
     use serde_json::json;
-    use settings::SettingsStore;
+    use settings::{SettingsStore, SplicingVec};
     use std::path::PathBuf;
     use unindent::Unindent;
     use util::path;
@@ -1068,10 +1068,10 @@ mod tests {
             use settings::SettingsStore;
             SettingsStore::update_global(cx, |store, cx| {
                 store.update_user_settings(cx, |settings| {
-                    settings.project.worktree.file_scan_exclusions = Some(vec![
+                    settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
                         "**/.secretdir".to_string(),
                         "**/.mymetadata".to_string(),
-                    ]);
+                    ]));
                     settings.project.worktree.private_files = Some(
                         vec![
                             "**/.mysecrets".to_string(),
@@ -1303,8 +1303,10 @@ mod tests {
         cx.update(|cx| {
             SettingsStore::update_global(cx, |store, cx| {
                 store.update_user_settings(cx, |settings| {
-                    settings.project.worktree.file_scan_exclusions =
-                        Some(vec!["**/.git".to_string(), "**/node_modules".to_string()]);
+                    settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
+                        "**/.git".to_string(),
+                        "**/node_modules".to_string(),
+                    ]));
                     settings.project.worktree.private_files =
                         Some(vec!["**/.env".to_string()].into());
                 });

crates/agent/src/tools/list_directory_tool.rs

@@ -342,7 +342,7 @@ mod tests {
     use indoc::indoc;
     use project::{FakeFs, Project};
     use serde_json::json;
-    use settings::SettingsStore;
+    use settings::{SettingsStore, SplicingVec};
     use std::path::PathBuf;
     use util::path;
 
@@ -578,11 +578,11 @@ mod tests {
         cx.update(|cx| {
             SettingsStore::update_global(cx, |store, cx| {
                 store.update_user_settings(cx, |settings| {
-                    settings.project.worktree.file_scan_exclusions = Some(vec![
+                    settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
                         "**/.secretdir".to_string(),
                         "**/.mymetadata".to_string(),
                         "**/.hidden_subdir".to_string(),
-                    ]);
+                    ]));
                     settings.project.worktree.private_files = Some(
                         vec![
                             "**/.mysecrets".to_string(),
@@ -740,8 +740,10 @@ mod tests {
         cx.update(|cx| {
             SettingsStore::update_global(cx, |store, cx| {
                 store.update_user_settings(cx, |settings| {
-                    settings.project.worktree.file_scan_exclusions =
-                        Some(vec!["**/.git".to_string(), "**/node_modules".to_string()]);
+                    settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
+                        "**/.git".to_string(),
+                        "**/node_modules".to_string(),
+                    ]));
                     settings.project.worktree.private_files =
                         Some(vec!["**/.env".to_string()].into());
                 });

crates/agent/src/tools/read_file_tool.rs

@@ -542,7 +542,7 @@ mod test {
     use gpui::{AppContext, TestAppContext, UpdateGlobal as _};
     use project::{FakeFs, Project};
     use serde_json::json;
-    use settings::SettingsStore;
+    use settings::{SettingsStore, SplicingVec};
     use std::path::PathBuf;
     use std::sync::Arc;
     use util::path;
@@ -1051,10 +1051,10 @@ mod test {
             use settings::SettingsStore;
             SettingsStore::update_global(cx, |store, cx| {
                 store.update_user_settings(cx, |settings| {
-                    settings.project.worktree.file_scan_exclusions = Some(vec![
+                    settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
                         "**/.secretdir".to_string(),
                         "**/.mymetadata".to_string(),
-                    ]);
+                    ]));
                     settings.project.worktree.private_files = Some(
                         vec![
                             "**/.mysecrets".to_string(),
@@ -1357,8 +1357,10 @@ mod test {
         cx.update(|cx| {
             SettingsStore::update_global(cx, |store, cx| {
                 store.update_user_settings(cx, |settings| {
-                    settings.project.worktree.file_scan_exclusions =
-                        Some(vec!["**/.git".to_string(), "**/node_modules".to_string()]);
+                    settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
+                        "**/.git".to_string(),
+                        "**/node_modules".to_string(),
+                    ]));
                     settings.project.worktree.private_files =
                         Some(vec!["**/.env".to_string()].into());
                 });

crates/collab/tests/integration/following_tests.rs

@@ -15,7 +15,7 @@ use gpui::{
 use language::Capability;
 use rpc::proto::PeerId;
 use serde_json::json;
-use settings::SettingsStore;
+use settings::{SettingsStore, SplicingVec};
 use text::{Point, ToPoint};
 use util::{path, rel_path::rel_path, test::sample_text};
 use workspace::{
@@ -1762,7 +1762,7 @@ async fn test_following_into_excluded_file(
             cx.update_global::<SettingsStore, _>(|store, cx| {
                 store.update_user_settings(cx, |settings| {
                     settings.project.worktree.file_scan_exclusions =
-                        Some(vec!["**/.git".to_string()]);
+                        Some(SplicingVec::from(vec!["**/.git".to_string()]));
                 });
             });
         });

crates/project/tests/integration/project_tests.rs

@@ -67,7 +67,7 @@ use project::{
 };
 use rand::{Rng as _, rngs::StdRng};
 use serde_json::json;
-use settings::{GlobalLspSettingsContent, SettingsStore};
+use settings::{GlobalLspSettingsContent, SettingsStore, SplicingVec};
 #[cfg(target_os = "linux")]
 use settings::{LocalSettingsKind, LocalSettingsPath};
 #[cfg(not(windows))]
@@ -13420,7 +13420,8 @@ async fn test_git_events_after_project_excludes_dot_git(cx: &mut gpui::TestAppCo
     cx.update(|cx| {
         SettingsStore::update_global(cx, |store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(vec!["foo".to_string()]);
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(vec!["foo".to_string()]));
             });
         });
     });
@@ -15268,7 +15269,8 @@ async fn test_rescan_with_gitignore(cx: &mut gpui::TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(Vec::new());
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(Vec::new()));
             });
         });
     });

crates/project_panel/src/project_panel_tests.rs

@@ -11,7 +11,7 @@ use menu::Cancel;
 use pretty_assertions::assert_eq;
 use project::{FakeFs, ProjectPath};
 use serde_json::json;
-use settings::{ProjectPanelAutoOpenSettings, SettingsStore};
+use settings::{ProjectPanelAutoOpenSettings, SettingsStore, SplicingVec};
 use smallvec::smallvec;
 use std::path::{Path, PathBuf};
 use util::{path, paths::PathStyle, rel_path::rel_path};
@@ -426,8 +426,10 @@ async fn test_exclusions_in_visible_list(cx: &mut gpui::TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions =
-                    Some(vec!["**/.git".to_string(), "**/4/**".to_string()]);
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
+                    "**/.git".to_string(),
+                    "**/4/**".to_string(),
+                ]));
             });
         });
     });
@@ -5562,7 +5564,8 @@ async fn test_autoreveal_and_gitignored_files(cx: &mut gpui::TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(Vec::new());
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(Vec::new()));
                 settings
                     .project_panel
                     .get_or_insert_default()
@@ -5864,7 +5867,8 @@ async fn test_gitignored_and_always_included(cx: &mut gpui::TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(Vec::new());
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(Vec::new()));
                 settings.project.worktree.file_scan_inclusions =
                     Some(vec!["always_included_but_ignored_dir/*".to_string()]);
                 settings
@@ -5988,7 +5992,8 @@ async fn test_explicit_reveal(cx: &mut gpui::TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(Vec::new());
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(Vec::new()));
                 settings
                     .project_panel
                     .get_or_insert_default()
@@ -6585,8 +6590,10 @@ async fn test_creating_excluded_entries(cx: &mut gpui::TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions =
-                    Some(vec!["excluded_dir".to_string(), "**/.git".to_string()]);
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
+                    "excluded_dir".to_string(),
+                    "**/.git".to_string(),
+                ]));
             });
         });
     });
@@ -11325,7 +11332,8 @@ pub(crate) fn init_test(cx: &mut TestAppContext) {
                     .project_panel
                     .get_or_insert_default()
                     .auto_fold_dirs = Some(false);
-                settings.project.worktree.file_scan_exclusions = Some(Vec::new());
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(Vec::new()));
                 settings.project.worktree.file_scan_depth = Some(0);
             });
         });
@@ -11346,7 +11354,8 @@ fn init_test_with_editor(cx: &mut TestAppContext) {
                     .project_panel
                     .get_or_insert_default()
                     .auto_fold_dirs = Some(false);
-                settings.project.worktree.file_scan_exclusions = Some(Vec::new());
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(Vec::new()));
                 settings.project.worktree.file_scan_depth = Some(0);
             });
         });
@@ -11368,7 +11377,8 @@ fn init_test_with_git_ui(cx: &mut TestAppContext) {
                     .project_panel
                     .get_or_insert_default()
                     .auto_fold_dirs = Some(false);
-                settings.project.worktree.file_scan_exclusions = Some(Vec::new());
+                settings.project.worktree.file_scan_exclusions =
+                    Some(SplicingVec::from(Vec::new()));
                 settings.project.worktree.file_scan_depth = Some(0);
             });
         });

crates/project_panel/src/tests/undo.rs

@@ -7,7 +7,7 @@ use fs::{FakeFs, Fs};
 use gpui::{App, BorrowAppContext, Context, Entity, VisualTestContext, Window};
 use project::Project;
 use serde_json::{Value, json};
-use settings::SettingsStore;
+use settings::{SettingsStore, SplicingVec};
 use std::path::Path;
 use std::sync::Arc;
 use workspace::{Item, MultiWorkspace, register_project_item};
@@ -617,10 +617,10 @@ async fn excluded_create_is_not_recorded(cx: &mut gpui::TestAppContext) {
     cx.update_app(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(vec![
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
                     "**/token.secret".to_string(),
                     "**/banana.secret".to_string(),
-                ]);
+                ]));
             });
         });
 

crates/settings/src/vscode_import.rs

@@ -1108,7 +1108,8 @@ impl VsCodeSettings {
                         .filter_map(|n| n.as_str().map(str::to_owned))
                         .collect::<Vec<_>>()
                 })
-                .filter(|r| !r.is_empty()),
+                .filter(|r| !r.is_empty())
+                .map(SplicingVec::from),
             file_scan_inclusions: self
                 .read_value("files.watcherInclude")
                 .and_then(|v| v.as_array())

crates/settings_content/src/project.rs

@@ -14,7 +14,7 @@ use util::serde::default_true;
 
 use crate::{
     AllLanguageSettingsContent, DelayMs, ExtendingVec, ParseStatus, ProjectTerminalSettingsContent,
-    RootUserSettings, SaturatingBool, fallible_options,
+    RootUserSettings, SaturatingBool, SplicingVec, fallible_options,
 };
 
 #[with_fallible_options]
@@ -123,6 +123,10 @@ pub struct WorktreeSettingsContent {
     /// Completely ignore files matching globs from `file_scan_exclusions`. Overrides
     /// `file_scan_inclusions`.
     ///
+    /// A `"..."` entry expands to the value being overridden, so
+    /// `["**/node_modules", "..."]` adds to the inherited globs instead of
+    /// replacing them. Leave `"..."` out to replace them.
+    ///
     /// Default: [
     ///   "**/.git",
     ///   "**/.svn",
@@ -134,7 +138,7 @@ pub struct WorktreeSettingsContent {
     ///   "**/.classpath",
     ///   "**/.settings"
     /// ]
-    pub file_scan_exclusions: Option<Vec<String>>,
+    pub file_scan_exclusions: Option<SplicingVec>,
 
     /// Always include files that match these globs when scanning for files, even if they're
     /// ignored by git. This setting is overridden by `file_scan_exclusions`.
@@ -936,6 +940,96 @@ pub enum GitHostingProviderKind {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::{REST_OF_FILE_SCAN_EXCLUSIONS, merge_from::MergeFrom};
+
+    fn exclusions(globs: &[&str]) -> WorktreeSettingsContent {
+        WorktreeSettingsContent {
+            file_scan_exclusions: Some(SplicingVec::from(
+                globs
+                    .iter()
+                    .map(|glob| glob.to_string())
+                    .collect::<Vec<_>>(),
+            )),
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn test_file_scan_exclusions_splice_rest_of_list() {
+        let defaults = exclusions(&["**/.git", "**/.DS_Store"]);
+
+        let mut extended = defaults.clone();
+        extended.merge_from(&exclusions(&[
+            "**/node_modules",
+            REST_OF_FILE_SCAN_EXCLUSIONS,
+        ]));
+        assert_eq!(
+            extended.file_scan_exclusions.unwrap().0,
+            vec!["**/node_modules", "**/.git", "**/.DS_Store"]
+        );
+
+        let mut replaced = defaults;
+        replaced.merge_from(&exclusions(&["**/node_modules"]));
+        assert_eq!(
+            replaced.file_scan_exclusions.unwrap().0,
+            vec!["**/node_modules"]
+        );
+    }
+
+    #[test]
+    fn test_file_scan_exclusions_splice_each_layer() {
+        let mut settings = exclusions(&["**/.git"]);
+        settings.merge_from(&exclusions(&[REST_OF_FILE_SCAN_EXCLUSIONS, "**/target"]));
+        settings.merge_from(&exclusions(&[REST_OF_FILE_SCAN_EXCLUSIONS, "**/dist"]));
+
+        assert_eq!(
+            settings.file_scan_exclusions.unwrap().0,
+            vec!["**/.git", "**/target", "**/dist"]
+        );
+    }
+
+    #[test]
+    fn test_file_scan_exclusions_splice_edge_cases() {
+        let mut repeated = exclusions(&["**/.git"]);
+        repeated.merge_from(&exclusions(&[
+            REST_OF_FILE_SCAN_EXCLUSIONS,
+            REST_OF_FILE_SCAN_EXCLUSIONS,
+        ]));
+        assert_eq!(repeated.file_scan_exclusions.unwrap().0, vec!["**/.git"]);
+
+        let mut relisted = exclusions(&["**/.git", "**/.DS_Store"]);
+        relisted.merge_from(&exclusions(&["**/.git", REST_OF_FILE_SCAN_EXCLUSIONS]));
+        assert_eq!(
+            relisted.file_scan_exclusions.unwrap().0,
+            vec!["**/.git", "**/.DS_Store"]
+        );
+
+        let mut cleared = exclusions(&["**/.git"]);
+        cleared.merge_from(&exclusions(&[]));
+        assert!(cleared.file_scan_exclusions.unwrap().0.is_empty());
+
+        let mut unchanged = exclusions(&["**/.git", "**/.DS_Store"]);
+        unchanged.merge_from(&exclusions(&[REST_OF_FILE_SCAN_EXCLUSIONS]));
+        assert_eq!(
+            unchanged.file_scan_exclusions.unwrap().0,
+            vec!["**/.git", "**/.DS_Store"]
+        );
+    }
+
+    #[test]
+    fn test_file_scan_exclusions_splice_without_a_base_layer() {
+        let mut settings = WorktreeSettingsContent::default();
+        settings.merge_from(&exclusions(&[REST_OF_FILE_SCAN_EXCLUSIONS, "**/target"]));
+
+        // `Option::merge_from` replaces a `None` base outright rather than
+        // splicing, so the sentinel survives here. `assets/settings/default.json`
+        // always populates this field, and `WorktreeSettings::from_settings`
+        // unwraps it, so no glob is ever compiled from this state.
+        assert_eq!(
+            settings.file_scan_exclusions.unwrap().0,
+            vec![REST_OF_FILE_SCAN_EXCLUSIONS, "**/target"]
+        );
+    }
 
     #[test]
     fn test_stdio_context_server_without_args() {

crates/settings_content/src/settings_content.rs

@@ -1399,6 +1399,46 @@ impl<T: Clone> merge_from::MergeFrom for ExtendingVec<T> {
     }
 }
 
+pub const REST_OF_FILE_SCAN_EXCLUSIONS: &str = "...";
+
+// A SplicingVec in the settings replaces the value it merges over, except that
+// a `...` entry expands to that previous value.
+//
+// This lets a settings file add to a list without restating what it inherits,
+// while omitting `...` still replaces the list outright. Unlike ExtendingVec,
+// entries can be dropped by leaving `...` out and listing what to keep.
+//
+// Entries collapse to their first occurrence, so naming a value that `...`
+// already covers keeps it at the position it was written in rather than
+// repeating it.
+#[derive(Default, Debug, Clone, PartialEq, Serialize, Deserialize, JsonSchema)]
+pub struct SplicingVec(pub Vec<String>);
+
+impl From<Vec<String>> for SplicingVec {
+    fn from(vec: Vec<String>) -> Self {
+        SplicingVec(vec)
+    }
+}
+
+impl merge_from::MergeFrom for SplicingVec {
+    fn merge_from(&mut self, other: &Self) {
+        let inherited = std::mem::take(&mut self.0);
+        self.0 = other
+            .0
+            .iter()
+            .flat_map(|entry| {
+                if entry == REST_OF_FILE_SCAN_EXCLUSIONS {
+                    inherited.clone()
+                } else {
+                    vec![entry.clone()]
+                }
+            })
+            .collect::<IndexSet<_>>()
+            .into_iter()
+            .collect();
+    }
+}
+
 // An ExtendingSet in the settings can only accumulate new values, and ignores
 // values that are already present, so merging the same source more than once
 // (e.g. re-importing VS Code settings) is idempotent.

crates/worktree/src/worktree_settings.rs

@@ -60,7 +60,7 @@ impl WorktreeSettings {
 impl Settings for WorktreeSettings {
     fn from_settings(content: &settings::SettingsContent) -> Self {
         let worktree = content.project.worktree.clone();
-        let file_scan_exclusions = worktree.file_scan_exclusions.unwrap();
+        let file_scan_exclusions = worktree.file_scan_exclusions.unwrap().0;
         let file_scan_inclusions = worktree.file_scan_inclusions.unwrap();
         let private_files = worktree.private_files.unwrap().0;
         let hidden_files = worktree.hidden_files.unwrap();

crates/worktree/tests/integration/worktree_tests.rs

@@ -15,7 +15,7 @@ use rpc::{AnyProtoClient, NoopProtoClient, proto};
 use worktree::{Entry, EntryKind, Event, PathChange, Worktree, WorktreeModelHandle};
 
 use serde_json::json;
-use settings::{LocalSettingsKind, LocalSettingsPath, SettingsStore, WorktreeId};
+use settings::{LocalSettingsKind, LocalSettingsPath, SettingsStore, SplicingVec, WorktreeId};
 use std::{
     cell::Cell,
     env,
@@ -2070,7 +2070,7 @@ async fn test_file_scan_inclusions(cx: &mut TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(vec![]);
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![]));
                 settings.project.worktree.file_scan_inclusions = Some(vec![
                     "node_modules/**/package.json".to_string(),
                     "**/.DS_Store".to_string(),
@@ -2141,7 +2141,7 @@ async fn test_file_scan_exclusions_overrules_inclusions(cx: &mut TestAppContext)
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
                 settings.project.worktree.file_scan_exclusions =
-                    Some(vec!["**/.DS_Store".to_string()]);
+                    Some(SplicingVec::from(vec!["**/.DS_Store".to_string()]));
                 settings.project.worktree.file_scan_inclusions =
                     Some(vec!["**/.DS_Store".to_string()]);
             });
@@ -2204,7 +2204,7 @@ async fn test_file_scan_inclusions_reindexes_on_setting_change(cx: &mut TestAppC
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(vec![]);
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![]));
                 settings.project.worktree.file_scan_inclusions =
                     Some(vec!["node_modules/**".to_string()]);
             });
@@ -2239,7 +2239,7 @@ async fn test_file_scan_inclusions_reindexes_on_setting_change(cx: &mut TestAppC
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(vec![]);
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![]));
                 settings.project.worktree.file_scan_inclusions = Some(vec![]);
             });
         });
@@ -2291,8 +2291,10 @@ async fn test_file_scan_exclusions(cx: &mut TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions =
-                    Some(vec!["**/foo/**".to_string(), "**/.DS_Store".to_string()]);
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
+                    "**/foo/**".to_string(),
+                    "**/.DS_Store".to_string(),
+                ]));
             });
         });
     });
@@ -2333,7 +2335,7 @@ async fn test_file_scan_exclusions(cx: &mut TestAppContext) {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
                 settings.project.worktree.file_scan_exclusions =
-                    Some(vec!["**/node_modules/**".to_string()]);
+                    Some(SplicingVec::from(vec!["**/node_modules/**".to_string()]));
             });
         });
     });
@@ -2487,11 +2489,11 @@ async fn test_fs_events_in_exclusions(cx: &mut TestAppContext) {
     cx.update(|cx| {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |settings| {
-                settings.project.worktree.file_scan_exclusions = Some(vec![
+                settings.project.worktree.file_scan_exclusions = Some(SplicingVec::from(vec![
                     "**/.git".to_string(),
                     "node_modules/".to_string(),
                     "build_output".to_string(),
-                ]);
+                ]));
             });
         });
     });

crates/zed/src/zed.rs

@@ -2938,7 +2938,7 @@ mod tests {
     use remote_server::{HeadlessAppState, HeadlessProject};
     use semver::Version;
     use serde_json::json;
-    use settings::{SaturatingBool, SettingsStore, watch_config_file};
+    use settings::{SaturatingBool, SettingsStore, SplicingVec, watch_config_file};
     use std::{
         path::{Path, PathBuf},
         sync::Arc,
@@ -4283,7 +4283,10 @@ mod tests {
             cx.update_global::<SettingsStore, _>(|store, cx| {
                 store.update_user_settings(cx, |project_settings| {
                     project_settings.project.worktree.file_scan_exclusions =
-                        Some(vec!["excluded_dir".to_string(), "**/.git".to_string()]);
+                        Some(SplicingVec::from(vec![
+                            "excluded_dir".to_string(),
+                            "**/.git".to_string(),
+                        ]));
                 });
             });
         });
@@ -6319,7 +6322,7 @@ mod tests {
         cx.update_global::<SettingsStore, _>(|store, cx| {
             store.update_user_settings(cx, |worktree_settings| {
                 worktree_settings.project.worktree.file_scan_exclusions =
-                    Some(vec![".zed".to_string()]);
+                    Some(SplicingVec::from(vec![".zed".to_string()]));
             });
         });
 

docs/src/reference/all-settings.md

@@ -2152,6 +2152,8 @@ The result is still `)))` and not `))))))`, which is what it would be by default
     "**/.svn",
     "**/.hg",
     "**/.jj",
+    "**/.sl",
+    "**/.repo",
     "**/CVS",
     "**/.DS_Store",
     "**/Thumbs.db",
@@ -2161,7 +2163,23 @@ The result is still `)))` and not `))))))`, which is what it would be by default
 }
 ```
 
-Note, specifying `file_scan_exclusions` in settings.json will override the defaults (shown above). If you are looking to exclude additional items you will need to include all the default values in your settings.
+Note that specifying `file_scan_exclusions` in `settings.json` will override the defaults (listed above). Use `"..."` to keep them:
+
+```json [settings]
+{
+  "file_scan_exclusions": ["**/node_modules", "..."]
+}
+```
+
+The `"..."` entry expands to the list you are overriding, so the example above excludes `node_modules` in addition to every default. Entries you list by name keep their position, and `"..."` fills in the inherited ones at that point in the list. If you want full control over what is excluded, omit `"..."` — only the entries you list by name will be used.
+
+| Configuration                | Result                               |
+| ---------------------------- | ------------------------------------ |
+| `["..."]`                    | The defaults, unchanged              |
+| `["**/node_modules", "..."]` | `**/node_modules`, then the defaults |
+| `["**/node_modules"]`        | `**/node_modules` only               |
+
+> Note: `"..."` resolves one settings layer at a time. In a project’s `.zed/settings.json` it expands to whatever your user settings resolved to, rather than to Zed’s defaults.
 
 ## File Scan Inclusions