galaxy/specs/APP-4115/TECH.md

TECH — Don't auto-add indexed repos to Directory tab colors

See also: PRODUCT.md in this directory. Linear: APP-4115.

Problem

Two coupled code changes are needed to deliver the product behavior:

1. Stop the CodebaseIndexManager-driven subscription that auto-populates TabSettings.directory_tab_colors with newly indexed paths.
2. Make the Add directory color control conditional: render the existing searchable FilterableDropdown when candidate repos exist, and render a plain ActionButton that opens the folder picker when the candidate set is empty.

Relevant code

• app/src/workspace/view.rs:2775-2790 — the subscription that calls DirectoryTabColors::merge_new_paths on every CodebaseIndexManagerEvent::SyncStateUpdated.
• app/src/workspace/tab_settings.rs:168-243 — DirectoryTabColor / DirectoryTabColors, including with_color and color_for_directory.
• app/src/settings_view/appearance_page.rs:1371-1378 — construction of DirectoryColorAddPicker.
• app/src/settings_view/appearance_page.rs:2416-2425 — handle_directory_color_add_picker_event.
• app/src/settings_view/appearance_page.rs:4632-4671 — helper functions for adding a directory tab color directly and opening the folder picker.
• app/src/settings_view/appearance_page.rs:4674-4815 — DirectoryTabColorsWidget, delete buttons, and rendering of the colors list.
• app/src/settings_view/directory_color_add_picker.rs — candidate computation, conditional rendering, and footer/button event emission.
• app/src/view_components/filterable_dropdown.rs — existing searchable dropdown behavior and pinned footer support.
• app/src/ai/persisted_workspace.rs:714-721 — PersistedWorkspace::workspaces() iterator.
• crates/ai/src/index/full_source_code_embedding/manager.rs:556-558 — get_codebase_paths.
• crates/warp_util/src/path.rs:85-114 — user_friendly_path helper used in the visible list.

Current state

• On startup and on every indexing sync-state update, the workspace view reads all CodebaseIndexManager paths and calls DirectoryTabColors::merge_new_paths, which inserts each canonical path into directory_tab_colors as Unassigned if not already present.
• DirectoryColorAddPicker already wraps FilterableDropdown and computes the correct candidate set for the searchable known-repo flow.
• The X button on each row dispatches RemoveDefaultDirectoryTabColor, which writes DirectoryTabColor::Suppressed rather than deleting the key.

Proposed changes

1. Remove the auto-add subscription

Delete the entire if FeatureFlag::DirectoryTabColors.is_enabled() { ctx.subscribe_to_model(&CodebaseIndexManager::handle(ctx), …) } block at app/src/workspace/view.rs:2775-2790. No replacement subscription is needed. Delete DirectoryTabColors::merge_new_paths and any tests or helpers whose only purpose was validating the old auto-add behavior.

2. Keep FilterableDropdown and add a fallback button

Keep app/src/settings_view/directory_color_add_picker.rs centered on the existing FilterableDropdown implementation. Add a second child view for the plain button and track whether the dropdown currently has any candidate rows.

pub struct DirectoryColorAddPicker {
    button: ViewHandle<ActionButton>,
    dropdown: ViewHandle<FilterableDropdown<DirectoryColorAddPickerAction>>,
    footer_mouse_state: MouseStateHandle,
    has_dropdown_items: bool,
}

DirectoryColorAddPicker::new:

• Creates the fallback ActionButton::new("Add directory color", SecondaryTheme).with_icon(Icon::Plus) and wires it to dispatch DirectoryColorAddPickerAction::AddNewDirectory.
• Creates the existing FilterableDropdown, keeps its current searchable behavior, and preserves the pinned + Add directory… footer.
• Subscribes to CodebaseIndexManager, PersistedWorkspace, and TabSettings so the candidate list refreshes when any source changes. refresh_items:
• Computes the candidate set using the existing pure helper.
• Converts candidates into DropdownItem<DirectoryColorAddPickerAction> values and passes them to dropdown.set_items(items, ctx).
• Sets has_dropdown_items = !items.is_empty().
• If the list becomes empty, closes the dropdown so the view can switch cleanly to the fallback button. render:
• If has_dropdown_items is true, render ChildView::new(&self.dropdown).
• Otherwise, render ChildView::new(&self.button). handle_action:
• Select(path) emits DirectoryColorAddPickerEvent::Selected(path) and lets FilterableDropdown close itself after dispatch.
• AddNewDirectory closes the dropdown if needed and emits DirectoryColorAddPickerEvent::RequestAddFromFilePicker.

3. Candidate-set helper

Keep compute_candidate_paths as the pure helper that:

• unions indexed and persisted paths,
• canonicalizes keys the same way DirectoryTabColors::with_color does,
• dedupes by canonical key,
• filters out entries already present with a non-Suppressed color,
• keeps Suppressed entries re-addable,
• filters out missing paths,
• sorts by canonical key.

4. Appearance page wiring

No appearance-page architectural change is needed beyond the existing DirectoryColorAddPicker integration:

• build_page continues to construct the picker and subscribe to its events.
• handle_directory_color_add_picker_event continues to map Selected(path) to add_directory_tab_color_path(path, ctx) and RequestAddFromFilePicker to open_directory_tab_color_folder_picker(ctx).
• The existing rebuild of directory_tab_color_delete_buttons and color_picker_dot_states in handle_tab_settings_event remains the source of truth for the visible list.

5. Suppressed behavior

No special-case behavior is needed beyond the existing helper and appearance-page add path:

• If a candidate row corresponds to a Suppressed key, selecting it transitions that entry back to Unassigned through with_color(path, DirectoryTabColor::Unassigned).
• If the user removes a row and it still exists in the indexed/persisted candidate set, it will reappear in the dropdown.

End-to-end flow

Candidate repos exist

1. DirectoryColorAddPicker renders the searchable dropdown.
2. The user opens it, filters if needed, and either selects a row or clicks the pinned footer.
3. Row selection emits Selected(path).
4. Footer click emits RequestAddFromFilePicker.

No candidate repos exist

1. DirectoryColorAddPicker renders the plain Add directory color button.
2. Clicking the button emits RequestAddFromFilePicker immediately.
3. The native folder picker opens, and on success the selected path is added through the existing appearance-page helper.

Indexing sync state updates

1. CodebaseIndexManagerEvent::SyncStateUpdated fires.
2. directory_tab_colors is not modified.
3. DirectoryColorAddPicker refreshes its candidate list and may switch between dropdown and button depending on whether any rows remain.

Risks and mitigations

• The control changes shape when the candidate count crosses zero. This is intentional. The dropdown only adds value when there are known repos to show.
• Suppressed semantics become less obvious. Keep the existing Suppressed write path unchanged so prefix-shadowing behavior remains stable.
• Stale dropdown state when candidates disappear. Close the dropdown in refresh_items whenever the candidate list becomes empty.

Testing and validation

• Unit tests on compute_candidate_paths covering dedupe, Suppressed, missing-path filtering, worktree inclusion, and sort order.
• Regression test confirming that CodebaseIndexManagerEvent::SyncStateUpdated no longer mutates directory_tab_colors.
• Manual validation of both control states:
  1. Dropdown shown when candidates exist.
  2. Fallback button shown when no candidates exist.
  3. Dropdown row selection adds an Unassigned entry.
  4. Dropdown footer opens the folder picker.
  5. Fallback button opens the folder picker.
• cargo check and cargo fmt --check.
• verify-ui-change-in-cloud for the final UI check.

Follow-ups

None.