fix: respect hideContextPercentage when FooterConfigDialog is closed without changes (#24773)

Co-authored-by: Coco Sheng <cocosheng@google.com>

packages/cli/src/config/footerItems.test.ts

@@ -153,5 +153,49 @@ describe('footerItems', () => {
       expect(state.orderedIds).toContain('auth');
       expect(state.selectedIds.has('auth')).toBe(true);
     });
+
+    it('includes context-used in selectedIds when hideContextPercentage is false and items is undefined', () => {
+      const settings = createMockSettings({
+        ui: {
+          footer: {
+            hideContextPercentage: false,
+          },
+        },
+      }).merged;
+
+      const state = resolveFooterState(settings);
+      expect(state.selectedIds.has('context-used')).toBe(true);
+      expect(state.orderedIds).toContain('context-used');
+    });
+
+    it('does not include context-used in selectedIds when hideContextPercentage is true (default)', () => {
+      const settings = createMockSettings({
+        ui: {
+          footer: {
+            hideContextPercentage: true,
+          },
+        },
+      }).merged;
+
+      const state = resolveFooterState(settings);
+      expect(state.selectedIds.has('context-used')).toBe(false);
+      // context-used should still be in orderedIds (as unselected)
+      expect(state.orderedIds).toContain('context-used');
+    });
+
+    it('persisted items array takes precedence over hideContextPercentage', () => {
+      const settings = createMockSettings({
+        ui: {
+          footer: {
+            items: ['workspace', 'model-name'],
+            hideContextPercentage: false,
+          },
+        },
+      }).merged;
+
+      const state = resolveFooterState(settings);
+      // items array explicitly omits context-used, so it should not be selected
+      expect(state.selectedIds.has('context-used')).toBe(false);
+    });
   });
 });

packages/cli/src/ui/components/FooterConfigDialog.tsx

@@ -13,7 +13,11 @@ import { useUIState } from '../contexts/UIStateContext.js';
 import { useKeypress, type Key } from '../hooks/useKeypress.js';
 import { Command } from '../key/keyMatchers.js';
 import { FooterRow, type FooterRowItem } from './Footer.js';
-import { ALL_ITEMS, resolveFooterState } from '../../config/footerItems.js';
+import {
+  ALL_ITEMS,
+  resolveFooterState,
+  deriveItemsFromLegacySettings,
+} from '../../config/footerItems.js';
 import { SettingScope } from '../../config/settings.js';
 import { BaseSelectionList } from './shared/BaseSelectionList.js';
 import type { SelectionListItem } from '../hooks/useSelectionList.js';
@@ -137,17 +141,16 @@ export const FooterConfigDialog: React.FC<FooterConfigDialogProps> = ({
   const handleSaveAndClose = useCallback(() => {
     const finalItems = orderedIds.filter((id: string) => selectedIds.has(id));
     const currentSetting = settings.merged.ui?.footer?.items;
-    if (JSON.stringify(finalItems) !== JSON.stringify(currentSetting)) {
+    // When items haven't been explicitly set yet (legacy mode), compare against
+    // the legacy-derived items to avoid persisting items and silently overriding
+    // legacy boolean settings like hideContextPercentage.
+    const effectiveCurrent =
+      currentSetting ?? deriveItemsFromLegacySettings(settings.merged);
+    if (JSON.stringify(finalItems) !== JSON.stringify(effectiveCurrent)) {
       setSetting(SettingScope.User, 'ui.footer.items', finalItems);
     }
     onClose?.();
-  }, [
-    orderedIds,
-    selectedIds,
-    setSetting,
-    settings.merged.ui?.footer?.items,
-    onClose,
-  ]);
+  }, [orderedIds, selectedIds, setSetting, settings.merged, onClose]);
 
   const handleResetToDefaults = useCallback(() => {
     setSetting(SettingScope.User, 'ui.footer.items', undefined);