fix: Preserve default select when saving search (#1986)

## Summary

This PR fixes a bug which caused searches with the defaultSelectExpression to be saved with an empty `select` value, resulting in no select value appearing when loading the saved search.

The fix is to save the default select expression when there is no select value in the `searchedConfig` value (from the URL params), which corresponds to the case in which the default select expression is shown on the (non-saved) search page.

### Screenshots or video

Before:

https://github.com/user-attachments/assets/2b578dab-2085-4e64-a79c-c2e6e8f085fa

After:

https://github.com/user-attachments/assets/bf713b86-a454-4fc8-9ed7-5370e2e665e0

### How to test locally or on Vercel

You can reproduce the behavior in the preview environment following the video demo above.

### References



- Linear Issue: Closes HDX-3298
- Related PRs:

Author: pulpdrew

.changeset/good-socks-leave.md

@@ -0,0 +1,5 @@
+---
+"@hyperdx/app": patch
+---
+
+fix: Preserve default select when saving search

packages/app/src/DBSearchPage.tsx

@@ -2,7 +2,6 @@ import {
   FormEvent,
   FormEventHandler,
   memo,
-  SetStateAction,
   useCallback,
   useEffect,
   useMemo,
@@ -346,6 +345,13 @@ function SaveSearchModalComponent({
   const createSavedSearch = useCreateSavedSearch();
   const updateSavedSearch = useUpdateSavedSearch();
 
+  const { data: sourceObj } = useSource({
+    id: searchedConfig.source,
+    kinds: [SourceKind.Log, SourceKind.Trace],
+  });
+  const effectiveSelect =
+    searchedConfig.select || sourceObj?.defaultTableSelectExpression || '';
+
   const onSubmit = (e: FormEvent<HTMLFormElement>) => {
     e.preventDefault();
 
@@ -359,7 +365,7 @@ function SaveSearchModalComponent({
           {
             id: savedSearchId,
             name,
-            select: searchedConfig.select ?? '',
+            select: effectiveSelect,
             where: searchedConfig.where ?? '',
             whereLanguage:
               searchedConfig.whereLanguage ?? getStoredLanguage() ?? 'lucene',
@@ -378,7 +384,7 @@ function SaveSearchModalComponent({
         createSavedSearch.mutate(
           {
             name,
-            select: searchedConfig.select ?? '',
+            select: effectiveSelect,
             where: searchedConfig.where ?? '',
             whereLanguage:
               searchedConfig.whereLanguage ?? getStoredLanguage() ?? 'lucene',

packages/app/tests/e2e/features/search/saved-search.spec.ts

@@ -303,6 +303,49 @@ test.describe('Saved Search Functionality', () => {
     },
   );
 
+  test(
+    'should preserve default SELECT when saving a search',
+    {},
+    async ({ page }) => {
+      let savedSearchUrl: string;
+
+      await test.step('Create saved search without setting a custom select', async () => {
+        await searchPage.openSaveSearchModal();
+        await searchPage.savedSearchModal.saveSearchAndWaitForNavigation(
+          'Default Select Navigation Test',
+        );
+
+        savedSearchUrl = page.url().split('?')[0];
+      });
+
+      await test.step('Verify default SELECT is loaded', async () => {
+        const selectEditor = searchPage.getSELECTEditor();
+        const selectContent = await selectEditor.textContent();
+        expect(selectContent).toContain(
+          'Timestamp, ServiceName, SeverityText, Body',
+        );
+      });
+
+      await test.step('Navigate to dashboards page', async () => {
+        await page.goto('/dashboards');
+        await expect(page.getByTestId('dashboard-page')).toBeVisible();
+      });
+
+      await test.step('Navigate back to saved search', async () => {
+        await page.goto(savedSearchUrl);
+        await expect(page.getByTestId('search-page')).toBeVisible();
+      });
+
+      await test.step('Verify default SELECT is loaded', async () => {
+        const selectEditor = searchPage.getSELECTEditor();
+        const selectContent = await selectEditor.textContent();
+        expect(selectContent).toContain(
+          'Timestamp, ServiceName, SeverityText, Body',
+        );
+      });
+    },
+  );
+
   test(
     'should handle navigation via browser back button',
     {},