fix(playwright): address review feedback on de-flake change

Three follow-ups from /review-code on the list-spec de-flake work:

- Revert toast assertions to expect(toast.getSuccess()).toBeVisible().
  The previous switch to toast.getSuccess().waitFor({ state: 'visible' })
  was a no-op: both APIs poll for visibility, so neither catches a fast
  auto-dismiss between polls. The expect() form fails as an assertion
  (clearer diff, counted in reports). Misleading "use waitFor so we
  detect auto-dismiss" comments are gone too.

- Drop redundant waitFor({ state: 'visible' }) calls in BulkSelect's
  selectRow / deselectRow / clickAction. Locator.check()/click() already
  auto-wait for visibility, stability, and enabled state. The
  expect(checkbox).toBeChecked() assertion -- which is the actual race
  guard against React state propagation -- stays.

- Expand the DeleteConfirmationModal.clickDelete docstring to explain
  why it bypasses Modal.clickFooterButton: the footer button label is
  i18n'd, so name-based lookups break in non-English locales.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/superset-docs-deploy.yml

@@ -17,6 +17,16 @@ on:
 
   workflow_dispatch: {}
 
+# Serialize deploys: the action pushes to apache/superset-site without
+# rebasing, so concurrent runs race on the final push and the loser fails
+# with `! [rejected] asf-site -> asf-site (fetch first)`. Cancel any
+# in-progress run as soon as a newer one starts — the destination repo
+# isn't touched until the final push step, so canceling mid-build is safe,
+# and the freshest content always wins.
+concurrency:
+  group: docs-deploy-asf-site
+  cancel-in-progress: true
+
 jobs:
   config:
     runs-on: ubuntu-24.04

superset-frontend/playwright/components/ListView/BulkSelect.ts

@@ -17,12 +17,13 @@
  * under the License.
  */
 
-import { Locator, Page } from '@playwright/test';
+import { Locator, Page, expect } from '@playwright/test';
 import { Button, Checkbox, Table } from '../core';
 
 const BULK_SELECT_SELECTORS = {
   CONTROLS: '[data-test="bulk-select-controls"]',
   ACTION: '[data-test="bulk-select-action"]',
+  HEADER_TOGGLE: '[data-test="header-toggle-all"]',
 } as const;
 
 /**
@@ -56,10 +57,17 @@ export class BulkSelect {
   }
 
   /**
-   * Enables bulk selection mode by clicking the toggle button
+   * Enables bulk selection mode by clicking the toggle button.
+   *
+   * Waits for the bulk-select column header checkbox to render so the next
+   * row interaction does not race the table re-render that adds the
+   * checkbox column.
    */
   async enable(): Promise<void> {
     await this.getToggleButton().click();
+    await this.page
+      .locator(BULK_SELECT_SELECTORS.HEADER_TOGGLE)
+      .waitFor({ state: 'visible' });
   }
 
   /**
@@ -72,19 +80,27 @@ export class BulkSelect {
   }
 
   /**
-   * Selects a row's checkbox in bulk select mode
+   * Selects a row's checkbox in bulk select mode.
+   * Asserts the checkbox is checked afterwards so any state-update race
+   * surfaces here rather than as a missing bulk-action button later.
    * @param rowName - The name/text identifying the row to select
    */
   async selectRow(rowName: string): Promise<void> {
-    await this.getRowCheckbox(rowName).check();
+    const checkbox = this.getRowCheckbox(rowName);
+    await checkbox.check();
+    await expect(checkbox.element).toBeChecked();
   }
 
   /**
-   * Deselects a row's checkbox in bulk select mode
+   * Deselects a row's checkbox in bulk select mode.
+   * Mirrors selectRow: asserts the unchecked state so any lingering selection
+   * surfaces here rather than as a stale bulk-action count later.
    * @param rowName - The name/text identifying the row to deselect
    */
   async deselectRow(rowName: string): Promise<void> {
-    await this.getRowCheckbox(rowName).uncheck();
+    const checkbox = this.getRowCheckbox(rowName);
+    await checkbox.uncheck();
+    await expect(checkbox.element).not.toBeChecked();
   }
 
   /**
@@ -107,10 +123,11 @@ export class BulkSelect {
   }
 
   /**
-   * Clicks a bulk action button by name (e.g., "Export", "Delete")
+   * Clicks a bulk action button by name (e.g., "Export", "Delete").
    * @param actionName - The name of the bulk action to click
    */
   async clickAction(actionName: string): Promise<void> {
-    await this.getActionButton(actionName).click();
+    const button = this.getActionButton(actionName);
+    await button.click();
   }
 }

superset-frontend/playwright/components/modals/DeleteConfirmationModal.ts

@@ -17,6 +17,7 @@
  * under the License.
  */
 
+import { expect } from '@playwright/test';
 import { Modal, Input } from '../core';
 
 /**
@@ -27,7 +28,8 @@ import { Modal, Input } from '../core';
  */
 export class DeleteConfirmationModal extends Modal {
   private static readonly SELECTORS = {
-    CONFIRMATION_INPUT: 'input[type="text"]',
+    CONFIRMATION_INPUT: '[data-test="delete-modal-input"]',
+    CONFIRM_BUTTON: '[data-test="modal-confirm-button"]',
   };
 
   /**
@@ -36,12 +38,16 @@ export class DeleteConfirmationModal extends Modal {
   private get confirmationInput(): Input {
     return new Input(
       this.page,
-      this.body.locator(DeleteConfirmationModal.SELECTORS.CONFIRMATION_INPUT),
+      this.element.locator(
+        DeleteConfirmationModal.SELECTORS.CONFIRMATION_INPUT,
+      ),
     );
   }
 
   /**
    * Fills the confirmation input with the specified text.
+   * Waits for the input to be visible before filling so callers don't race
+   * with the modal's open animation / focus effect.
    *
    * @param confirmationText - The text to type
    * @param options - Optional fill options (timeout, force)
@@ -57,11 +63,25 @@ export class DeleteConfirmationModal extends Modal {
     confirmationText: string,
     options?: { timeout?: number; force?: boolean },
   ): Promise<void> {
+    await this.confirmationInput.element.waitFor({
+      state: 'visible',
+      timeout: options?.timeout,
+    });
     await this.confirmationInput.fill(confirmationText, options);
   }
 
   /**
-   * Clicks the Delete button in the footer
+   * Clicks the Delete button in the footer.
+   *
+   * Targets the confirm button by data-test rather than going through
+   * Modal.clickFooterButton, which finds buttons by their visible text. The
+   * button label is i18n'd ("Delete" / "Supprimer" / …) so name-based lookups
+   * break in non-English locales.
+   *
+   * Also waits for the button to become enabled before clicking: it is
+   * disabled until the confirmation text matches "DELETE", and React's state
+   * update from fillConfirmationInput is asynchronous, so an immediate click
+   * can race the disabled→enabled transition.
    *
    * @param options - Optional click options (timeout, force, delay)
    */
@@ -70,6 +90,10 @@ export class DeleteConfirmationModal extends Modal {
     force?: boolean;
     delay?: number;
   }): Promise<void> {
-    await this.clickFooterButton('Delete', options);
+    const confirmButton = this.element.locator(
+      DeleteConfirmationModal.SELECTORS.CONFIRM_BUTTON,
+    );
+    await expect(confirmButton).toBeEnabled({ timeout: options?.timeout });
+    await confirmButton.click(options);
   }
 }

superset-frontend/playwright/tests/chart/chart-list.spec.ts

@@ -32,6 +32,7 @@ import {
   expectStatusOneOf,
   expectValidExportZip,
 } from '../../helpers/api/assertions';
+import { TIMEOUT } from '../../utils/constants';
 
 /**
  * Extend testWithAssets with chartListPage navigation (beforeEach equivalent).
@@ -62,8 +63,11 @@ test('should delete a chart with confirmation', async ({
   await chartListPage.goto();
   await chartListPage.waitForTableLoad();
 
-  // Verify chart is visible in list
-  await expect(chartListPage.getChartRow(chartName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created chart appears.
+  await expect(chartListPage.getChartRow(chartName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Click delete action button
   await chartListPage.clickDeleteAction(chartName);
@@ -81,12 +85,12 @@ test('should delete a chart with confirmation', async ({
   // Modal should close
   await deleteModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible();
 
-  // Verify chart is removed from list
-  await expect(chartListPage.getChartRow(chartName)).not.toBeVisible();
+  // Verify chart is removed from list (deleted rows leave the DOM)
+  await expect(chartListPage.getChartRow(chartName)).toHaveCount(0);
 
   // Backend verification: API returns 404
   await expectDeleted(page, ENDPOINTS.CHART, chartId, {
@@ -111,8 +115,11 @@ test('should edit chart name via properties modal', async ({
   await chartListPage.goto();
   await chartListPage.waitForTableLoad();
 
-  // Verify chart is visible in list
-  await expect(chartListPage.getChartRow(chartName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created chart appears.
+  await expect(chartListPage.getChartRow(chartName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Click edit action to open properties modal
   await chartListPage.clickEditAction(chartName);
@@ -137,7 +144,7 @@ test('should edit chart name via properties modal', async ({
   // Modal should close
   await propertiesModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible();
 
@@ -164,8 +171,11 @@ test('should export a chart as a zip file', async ({
   await chartListPage.goto();
   await chartListPage.waitForTableLoad();
 
-  // Verify chart is visible in list
-  await expect(chartListPage.getChartRow(chartName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created chart appears.
+  await expect(chartListPage.getChartRow(chartName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Set up API response intercept for export endpoint
   const exportResponsePromise = waitForGet(page, ENDPOINTS.CHART_EXPORT);
@@ -202,9 +212,14 @@ test('should bulk delete multiple charts', async ({
   await chartListPage.goto();
   await chartListPage.waitForTableLoad();
 
-  // Verify both charts are visible in list
-  await expect(chartListPage.getChartRow(chart1.name)).toBeVisible();
-  await expect(chartListPage.getChartRow(chart2.name)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created charts appear.
+  await expect(chartListPage.getChartRow(chart1.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(chartListPage.getChartRow(chart2.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Enable bulk select mode
   await chartListPage.clickBulkSelectButton();
@@ -229,13 +244,13 @@ test('should bulk delete multiple charts', async ({
   // Modal should close
   await deleteModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible();
 
-  // Verify both charts are removed from list
-  await expect(chartListPage.getChartRow(chart1.name)).not.toBeVisible();
-  await expect(chartListPage.getChartRow(chart2.name)).not.toBeVisible();
+  // Verify both charts are removed from list (deleted rows leave the DOM)
+  await expect(chartListPage.getChartRow(chart1.name)).toHaveCount(0);
+  await expect(chartListPage.getChartRow(chart2.name)).toHaveCount(0);
 
   // Backend verification: Both return 404
   for (const chart of [chart1, chart2]) {
@@ -259,8 +274,11 @@ test('should edit chart name from card view', async ({ page, testAssets }) => {
   await cardListPage.gotoCardView();
   await cardListPage.waitForCardLoad();
 
-  // Verify chart card is visible
-  await expect(cardListPage.getChartCard(chartName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created chart card appears.
+  await expect(cardListPage.getChartCard(chartName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Open card dropdown and click edit
   await cardListPage.clickCardEditAction(chartName);
@@ -285,13 +303,16 @@ test('should edit chart name from card view', async ({ page, testAssets }) => {
   // Modal should close
   await propertiesModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible();
 
   // Verify the renamed card appears in card view and old name is gone
-  await expect(cardListPage.getChartCard(newName)).toBeVisible();
-  await expect(cardListPage.getChartCard(chartName)).not.toBeVisible();
+  // (the old card name is removed from the DOM after the rename re-render).
+  await expect(cardListPage.getChartCard(newName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(cardListPage.getChartCard(chartName)).toHaveCount(0);
 
   // Backend verification: API returns updated name
   const response = await apiGetChart(page, chartId);
@@ -304,6 +325,11 @@ test('should bulk export multiple charts', async ({
   chartListPage,
   testAssets,
 }) => {
+  // Chains create×2 → refresh → bulk select → export. Matches the
+  // sibling bulk-delete test's budget so the export response wait below
+  // can exceed the 30s default without hitting the test timeout.
+  test.setTimeout(TIMEOUT.SLOW_TEST);
+
   // Create 2 throwaway charts for bulk export
   const [chart1, chart2] = await Promise.all([
     createTestChart(page, testAssets, test.info(), {
@@ -318,9 +344,14 @@ test('should bulk export multiple charts', async ({
   await chartListPage.goto();
   await chartListPage.waitForTableLoad();
 
-  // Verify both charts are visible in list
-  await expect(chartListPage.getChartRow(chart1.name)).toBeVisible();
-  await expect(chartListPage.getChartRow(chart2.name)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created charts appear.
+  await expect(chartListPage.getChartRow(chart1.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(chartListPage.getChartRow(chart2.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Enable bulk select mode
   await chartListPage.clickBulkSelectButton();
@@ -329,8 +360,12 @@ test('should bulk export multiple charts', async ({
   await chartListPage.selectChartCheckbox(chart1.name);
   await chartListPage.selectChartCheckbox(chart2.name);
 
-  // Set up API response intercept for export endpoint
-  const exportResponsePromise = waitForGet(page, ENDPOINTS.CHART_EXPORT);
+  // Set up API response intercept BEFORE the click that triggers it.
+  // Exports of multiple charts can take longer than 30s under load,
+  // so use SLOW_TEST instead of the default test-timeout-bound budget.
+  const exportResponsePromise = waitForGet(page, ENDPOINTS.CHART_EXPORT, {
+    timeout: TIMEOUT.SLOW_TEST,
+  });
 
   // Click bulk export action
   await chartListPage.clickBulkAction('Export');

superset-frontend/playwright/tests/dashboard/dashboard-list.spec.ts

@@ -68,33 +68,34 @@ test('should delete a dashboard with confirmation', async ({
   await dashboardListPage.goto();
   await dashboardListPage.waitForTableLoad();
 
-  // Verify dashboard is visible in list
-  await expect(dashboardListPage.getDashboardRow(dashboardName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created dashboard appears.
+  await expect(dashboardListPage.getDashboardRow(dashboardName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Click delete action button
   await dashboardListPage.clickDeleteAction(dashboardName);
 
   // Delete confirmation modal should appear
   const deleteModal = new DeleteConfirmationModal(page);
-  await deleteModal.waitForVisible();
+  await deleteModal.waitForReady();
 
   // Type "DELETE" to confirm
   await deleteModal.fillConfirmationInput('DELETE');
 
-  // Click the Delete button
+  // Click the Delete button (waits for it to become enabled)
   await deleteModal.clickDelete();
 
   // Modal should close
   await deleteModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible();
 
   // Verify dashboard is removed from list
-  await expect(
-    dashboardListPage.getDashboardRow(dashboardName),
-  ).not.toBeVisible();
+  await expect(dashboardListPage.getDashboardRow(dashboardName)).toHaveCount(0);
 
   // Backend verification: API returns 404
   await expectDeleted(page, ENDPOINTS.DASHBOARD, dashboardId, {
@@ -119,8 +120,11 @@ test('should export a dashboard as a zip file', async ({
   await dashboardListPage.goto();
   await dashboardListPage.waitForTableLoad();
 
-  // Verify dashboard is visible in list
-  await expect(dashboardListPage.getDashboardRow(dashboardName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created dashboard appears.
+  await expect(dashboardListPage.getDashboardRow(dashboardName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Set up API response intercept for export endpoint
   const exportResponsePromise = waitForGet(page, ENDPOINTS.DASHBOARD_EXPORT);
@@ -157,13 +161,14 @@ test('should bulk delete multiple dashboards', async ({
   await dashboardListPage.goto();
   await dashboardListPage.waitForTableLoad();
 
-  // Verify both dashboards are visible in list
-  await expect(
-    dashboardListPage.getDashboardRow(dashboard1.name),
-  ).toBeVisible();
-  await expect(
-    dashboardListPage.getDashboardRow(dashboard2.name),
-  ).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created dashboards appear.
+  await expect(dashboardListPage.getDashboardRow(dashboard1.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(dashboardListPage.getDashboardRow(dashboard2.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Enable bulk select mode
   await dashboardListPage.clickBulkSelectButton();
@@ -188,17 +193,17 @@ test('should bulk delete multiple dashboards', async ({
   // Modal should close
   await deleteModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible();
 
-  // Verify both dashboards are removed from list
-  await expect(
-    dashboardListPage.getDashboardRow(dashboard1.name),
-  ).not.toBeVisible();
-  await expect(
-    dashboardListPage.getDashboardRow(dashboard2.name),
-  ).not.toBeVisible();
+  // Verify both dashboards are removed from list (deleted rows leave the DOM)
+  await expect(dashboardListPage.getDashboardRow(dashboard1.name)).toHaveCount(
+    0,
+  );
+  await expect(dashboardListPage.getDashboardRow(dashboard2.name)).toHaveCount(
+    0,
+  );
 
   // Backend verification: Both return 404
   for (const dashboard of [dashboard1, dashboard2]) {
@@ -213,6 +218,11 @@ test('should bulk export multiple dashboards', async ({
   dashboardListPage,
   testAssets,
 }) => {
+  // Chains create×2 → refresh → bulk select → export. Matches the
+  // sibling bulk-delete test's budget so the export response wait below
+  // can exceed the 30s default without hitting the test timeout.
+  test.setTimeout(TIMEOUT.SLOW_TEST);
+
   // Create 2 throwaway dashboards for bulk export
   const [dashboard1, dashboard2] = await Promise.all([
     createTestDashboard(page, testAssets, test.info(), {
@@ -227,25 +237,30 @@ test('should bulk export multiple dashboards', async ({
   await dashboardListPage.goto();
   await dashboardListPage.waitForTableLoad();
 
-  // Verify both dashboards are visible in list
-  await expect(
-    dashboardListPage.getDashboardRow(dashboard1.name),
-  ).toBeVisible();
-  await expect(
-    dashboardListPage.getDashboardRow(dashboard2.name),
-  ).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created dashboards appear.
+  await expect(dashboardListPage.getDashboardRow(dashboard1.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(dashboardListPage.getDashboardRow(dashboard2.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
-  // Enable bulk select mode
+  // Enable bulk select mode (waits for the checkbox column to render)
   await dashboardListPage.clickBulkSelectButton();
 
-  // Select both dashboards
+  // Select both dashboards (each call asserts the checkbox is checked)
   await dashboardListPage.selectDashboardCheckbox(dashboard1.name);
   await dashboardListPage.selectDashboardCheckbox(dashboard2.name);
 
-  // Set up API response intercept for export endpoint
-  const exportResponsePromise = waitForGet(page, ENDPOINTS.DASHBOARD_EXPORT);
+  // Set up API response intercept BEFORE the click that triggers it.
+  // Exports of multiple dashboards can take longer than 30s under load,
+  // so use SLOW_TEST instead of the default test-timeout-bound budget.
+  const exportResponsePromise = waitForGet(page, ENDPOINTS.DASHBOARD_EXPORT, {
+    timeout: TIMEOUT.SLOW_TEST,
+  });
 
-  // Click bulk export action
+  // Click bulk export action (waits for the action button to render)
   await dashboardListPage.clickBulkAction('Export');
 
   // Wait for export API response and validate zip contains both dashboards
@@ -293,12 +308,12 @@ test.describe('import dashboard', () => {
       label: `Dashboard ${dashboardId}`,
     });
 
-    // Refresh to confirm dashboard is no longer in the list
+    // Refresh to confirm dashboard is no longer in the list (deleted rows leave the DOM)
     await dashboardListPage.goto();
     await dashboardListPage.waitForTableLoad();
-    await expect(
-      dashboardListPage.getDashboardRow(dashboardName),
-    ).not.toBeVisible();
+    await expect(dashboardListPage.getDashboardRow(dashboardName)).toHaveCount(
+      0,
+    );
 
     // Click the import button
     await dashboardListPage.clickImportButton();
@@ -350,7 +365,7 @@ test.describe('import dashboard', () => {
     // Modal should close on success
     await importModal.waitForHidden({ timeout: TIMEOUT.FILE_IMPORT });
 
-    // Verify success toast appears
+    // Verify success toast appears.
     const toast = new Toast(page);
     await expect(toast.getSuccess()).toBeVisible({ timeout: 10000 });
 
@@ -358,10 +373,11 @@ test.describe('import dashboard', () => {
     await dashboardListPage.goto();
     await dashboardListPage.waitForTableLoad();
 
-    // Verify dashboard appears in list
-    await expect(
-      dashboardListPage.getDashboardRow(dashboardName),
-    ).toBeVisible();
+    // The list query is asynchronous; allow extra time on slow CI before the
+    // freshly-imported dashboard appears.
+    await expect(dashboardListPage.getDashboardRow(dashboardName)).toBeVisible({
+      timeout: TIMEOUT.API_RESPONSE,
+    });
 
     // Track for cleanup: look up the reimported dashboard by title
     const reimported = await getDashboardByName(page, dashboardName);

superset-frontend/playwright/tests/dataset/dataset-list.spec.ts

@@ -107,8 +107,11 @@ test('should delete a dataset with confirmation', async ({
   await datasetListPage.goto();
   await datasetListPage.waitForTableLoad();
 
-  // Verify dataset is visible in list
-  await expect(datasetListPage.getDatasetRow(datasetName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created dataset appears.
+  await expect(datasetListPage.getDatasetRow(datasetName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Click delete action button
   await datasetListPage.clickDeleteAction(datasetName);
@@ -126,14 +129,13 @@ test('should delete a dataset with confirmation', async ({
   // Modal should close
   await deleteModal.waitForHidden();
 
-  // Verify success toast appears with correct message
+  // Verify success toast appears with correct message.
   const toast = new Toast(page);
-  const successToast = toast.getSuccess();
-  await expect(successToast).toBeVisible();
+  await expect(toast.getSuccess()).toBeVisible();
   await expect(toast.getMessage()).toContainText('Deleted');
 
-  // Verify dataset is removed from list
-  await expect(datasetListPage.getDatasetRow(datasetName)).not.toBeVisible();
+  // Verify dataset is removed from list (deleted rows leave the DOM)
+  await expect(datasetListPage.getDatasetRow(datasetName)).toHaveCount(0);
 
   // Verify via API that dataset no longer exists (404)
   await expectDeleted(page, ENDPOINTS.DATASET, datasetId, {
@@ -155,10 +157,13 @@ test('should duplicate a dataset with new name', async ({
   );
   const duplicateName = `duplicate_${Date.now()}_${test.info().parallelIndex}`;
 
-  // Navigate to list and verify original dataset is visible
+  // Navigate to list and verify original dataset is visible.
+  // The list query is asynchronous; allow extra time on slow CI.
   await datasetListPage.goto();
   await datasetListPage.waitForTableLoad();
-  await expect(datasetListPage.getDatasetRow(originalName)).toBeVisible();
+  await expect(datasetListPage.getDatasetRow(originalName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Set up response intercept to capture duplicate dataset ID
   const duplicateResponsePromise = waitForPost(
@@ -201,9 +206,14 @@ test('should duplicate a dataset with new name', async ({
   await datasetListPage.goto();
   await datasetListPage.waitForTableLoad();
 
-  // Verify both datasets exist in list
-  await expect(datasetListPage.getDatasetRow(originalName)).toBeVisible();
-  await expect(datasetListPage.getDatasetRow(duplicateName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // duplicate appears alongside the original.
+  await expect(datasetListPage.getDatasetRow(originalName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(datasetListPage.getDatasetRow(duplicateName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // API Verification: Fetch both datasets via detail API for consistent comparison
   // (list API may return undefined for fields that detail API returns as null)
@@ -256,6 +266,11 @@ test('should export multiple datasets via bulk select action', async ({
   datasetListPage,
   testAssets,
 }) => {
+  // Chains create×2 → refresh → bulk select → export. Matches the
+  // sibling bulk-delete test's budget so the export response wait below
+  // can exceed the 30s default without hitting the test timeout.
+  test.setTimeout(TIMEOUT.SLOW_TEST);
+
   // Create 2 throwaway datasets for bulk export
   const [dataset1, dataset2] = await Promise.all([
     createTestDataset(page, testAssets, test.info(), {
@@ -270,9 +285,14 @@ test('should export multiple datasets via bulk select action', async ({
   await datasetListPage.goto();
   await datasetListPage.waitForTableLoad();
 
-  // Verify both datasets are visible in list
-  await expect(datasetListPage.getDatasetRow(dataset1.name)).toBeVisible();
-  await expect(datasetListPage.getDatasetRow(dataset2.name)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created datasets appear.
+  await expect(datasetListPage.getDatasetRow(dataset1.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(datasetListPage.getDatasetRow(dataset2.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Enable bulk select mode
   await datasetListPage.clickBulkSelectButton();
@@ -281,8 +301,12 @@ test('should export multiple datasets via bulk select action', async ({
   await datasetListPage.selectDatasetCheckbox(dataset1.name);
   await datasetListPage.selectDatasetCheckbox(dataset2.name);
 
-  // Set up API response intercept for export endpoint
-  const exportResponsePromise = waitForGet(page, ENDPOINTS.DATASET_EXPORT);
+  // Set up API response intercept BEFORE the click that triggers it.
+  // Exports of multiple datasets can take longer than 30s under load,
+  // so use SLOW_TEST instead of the default test-timeout-bound budget.
+  const exportResponsePromise = waitForGet(page, ENDPOINTS.DATASET_EXPORT, {
+    timeout: TIMEOUT.SLOW_TEST,
+  });
 
   // Click bulk export action
   await datasetListPage.clickBulkAction('Export');
@@ -312,8 +336,11 @@ test('should edit dataset name via modal', async ({
   await datasetListPage.goto();
   await datasetListPage.waitForTableLoad();
 
-  // Verify dataset is visible in list
-  await expect(datasetListPage.getDatasetRow(datasetName)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created dataset appears.
+  await expect(datasetListPage.getDatasetRow(datasetName)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Click edit action to open modal
   await datasetListPage.clickEditAction(datasetName);
@@ -348,7 +375,7 @@ test('should edit dataset name via modal', async ({
   // Modal should close
   await editModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible({ timeout: 10000 });
 
@@ -377,9 +404,14 @@ test('should bulk delete multiple datasets', async ({
   await datasetListPage.goto();
   await datasetListPage.waitForTableLoad();
 
-  // Verify both datasets are visible in list
-  await expect(datasetListPage.getDatasetRow(dataset1.name)).toBeVisible();
-  await expect(datasetListPage.getDatasetRow(dataset2.name)).toBeVisible();
+  // The list query is asynchronous; allow extra time on slow CI before the
+  // freshly-created datasets appear.
+  await expect(datasetListPage.getDatasetRow(dataset1.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
+  await expect(datasetListPage.getDatasetRow(dataset2.name)).toBeVisible({
+    timeout: TIMEOUT.API_RESPONSE,
+  });
 
   // Enable bulk select mode
   await datasetListPage.clickBulkSelectButton();
@@ -404,13 +436,13 @@ test('should bulk delete multiple datasets', async ({
   // Modal should close
   await deleteModal.waitForHidden();
 
-  // Verify success toast appears
+  // Verify success toast appears.
   const toast = new Toast(page);
   await expect(toast.getSuccess()).toBeVisible();
 
-  // Verify both datasets are removed from list
-  await expect(datasetListPage.getDatasetRow(dataset1.name)).not.toBeVisible();
-  await expect(datasetListPage.getDatasetRow(dataset2.name)).not.toBeVisible();
+  // Verify both datasets are removed from list (deleted rows leave the DOM)
+  await expect(datasetListPage.getDatasetRow(dataset1.name)).toHaveCount(0);
+  await expect(datasetListPage.getDatasetRow(dataset2.name)).toHaveCount(0);
 
   // Verify via API that datasets no longer exist (404)
   await expectDeleted(page, ENDPOINTS.DATASET, dataset1.id, {
@@ -455,10 +487,10 @@ test.describe('import dataset', () => {
       label: `Dataset ${datasetId}`,
     });
 
-    // Refresh to confirm dataset is no longer in the list
+    // Refresh to confirm dataset is no longer in the list (deleted rows leave the DOM)
     await datasetListPage.goto();
     await datasetListPage.waitForTableLoad();
-    await expect(datasetListPage.getDatasetRow(datasetName)).not.toBeVisible();
+    await expect(datasetListPage.getDatasetRow(datasetName)).toHaveCount(0);
 
     // Click the import button
     await datasetListPage.clickImportButton();
@@ -507,7 +539,7 @@ test.describe('import dataset', () => {
     // Modal should close on success
     await importModal.waitForHidden({ timeout: TIMEOUT.FILE_IMPORT });
 
-    // Verify success toast appears
+    // Verify success toast appears.
     const toast = new Toast(page);
     await expect(toast.getSuccess()).toBeVisible({ timeout: 10000 });
 
@@ -515,8 +547,11 @@ test.describe('import dataset', () => {
     await datasetListPage.goto();
     await datasetListPage.waitForTableLoad();
 
-    // Verify dataset appears in list
-    await expect(datasetListPage.getDatasetRow(datasetName)).toBeVisible();
+    // The list query is asynchronous; allow extra time on slow CI before the
+    // freshly-imported dataset appears.
+    await expect(datasetListPage.getDatasetRow(datasetName)).toBeVisible({
+      timeout: TIMEOUT.API_RESPONSE,
+    });
 
     // Track for cleanup: the dataset import API returns {"message": "OK"}
     // with no ID, so look up the reimported dataset by name.

superset-frontend/plugins/plugin-chart-pivot-table/src/react-pivottable/PivotTable.tsx

@@ -17,16 +17,14 @@
  * under the License.
  */
 
-import { PureComponent } from 'react';
+import { memo } from 'react';
 import { TableRenderer } from './TableRenderers';
 import type { ComponentProps } from 'react';
 
 type PivotTableProps = ComponentProps<typeof TableRenderer>;
 
-class PivotTable extends PureComponent<PivotTableProps> {
-  render() {
-    return <TableRenderer {...this.props} />;
-  }
+function PivotTable(props: PivotTableProps) {
+  return <TableRenderer {...props} />;
 }
 
-export default PivotTable;
+export default memo(PivotTable);

superset-frontend/src/SqlLab/components/SaveDatasetModal/SaveDatasetModal.test.tsx

@@ -30,7 +30,7 @@ import fetchMock from 'fetch-mock';
 import { SaveDatasetModal } from 'src/SqlLab/components/SaveDatasetModal';
 import { createDatasource } from 'src/SqlLab/actions/sqlLab';
 import { user, testQuery, mockdatasets } from 'src/SqlLab/fixtures';
-import { FeatureFlag } from '@superset-ui/core';
+import { FeatureFlag, SupersetClient } from '@superset-ui/core';
 
 const mockedProps = {
   visible: true,
@@ -354,6 +354,131 @@ describe('SaveDatasetModal', () => {
     });
   });
 
+  const setupOverwriteFlow = async () => {
+    // Select the "Overwrite existing" radio
+    await userEvent.click(
+      screen.getByRole('radio', { name: /overwrite existing/i }),
+    );
+    // Open the select to load existing-dataset options
+    await userEvent.click(
+      screen.getByRole('combobox', { name: /existing dataset/i }),
+    );
+    // Advance timers to flush debounced fetches in AsyncSelect
+    await act(async () => {
+      jest.runAllTimers();
+    });
+    // Wait for the loading indicator to clear
+    await waitFor(() => {
+      const loading = screen.queryByText('Loading...');
+      expect(loading === null || !loading.checkVisibility()).toBe(true);
+    });
+    // Pick an existing dataset (use the listbox item, not the input mirror)
+    const options = await screen.findAllByText('coolest table 0');
+    await userEvent.click(options[1]);
+    // First overwrite click → confirmation screen
+    await userEvent.click(screen.getByRole('button', { name: /overwrite/i }));
+    // Wait for the confirmation screen to render
+    await screen.findByText(/are you sure you want to overwrite this dataset/i);
+    // Second overwrite click → triggers the PUT
+    await userEvent.click(screen.getByRole('button', { name: /overwrite/i }));
+  };
+
+  test('sends template_params when overwriting a dataset with include template parameters checked', async () => {
+    // @ts-expect-error
+    global.featureFlags = {
+      [FeatureFlag.EnableTemplateProcessing]: true,
+    };
+
+    const putSpy = jest
+      .spyOn(SupersetClient, 'put')
+      .mockResolvedValue({ json: { result: { id: 0 } } } as any);
+
+    const dummyDispatch = jest.fn().mockResolvedValue({});
+    useDispatchMock.mockReturnValue(dummyDispatch);
+    useSelectorMock.mockReturnValue({ ...user });
+
+    const propsWithTemplateParam = {
+      ...mockedProps,
+      datasource: {
+        ...testQuery,
+        templateParams: JSON.stringify({ my_param: 12, _filters: 'foo' }),
+      },
+    };
+    render(<SaveDatasetModal {...propsWithTemplateParam} />, {
+      useRedux: true,
+    });
+
+    // Check the "Include Template Parameters" checkbox
+    await userEvent.click(screen.getByRole('checkbox'));
+
+    await setupOverwriteFlow();
+
+    await waitFor(() => {
+      expect(
+        putSpy.mock.calls.some(([req]) =>
+          req.endpoint?.includes('api/v1/dataset/'),
+        ),
+      ).toBe(true);
+    });
+
+    const datasetPutCall = putSpy.mock.calls.find(([req]) =>
+      req.endpoint?.includes('api/v1/dataset/'),
+    )!;
+    const [req] = datasetPutCall;
+    expect(req.endpoint).toContain('override_columns=true');
+    const body = JSON.parse(req.body as string);
+    // _filters should be stripped, but my_param should be preserved
+    expect(body.template_params).toEqual(JSON.stringify({ my_param: 12 }));
+
+    putSpy.mockRestore();
+  });
+
+  test('does not send template_params when overwriting a dataset with include template parameters unchecked', async () => {
+    // @ts-expect-error
+    global.featureFlags = {
+      [FeatureFlag.EnableTemplateProcessing]: true,
+    };
+
+    const putSpy = jest
+      .spyOn(SupersetClient, 'put')
+      .mockResolvedValue({ json: { result: { id: 0 } } } as any);
+
+    const dummyDispatch = jest.fn().mockResolvedValue({});
+    useDispatchMock.mockReturnValue(dummyDispatch);
+    useSelectorMock.mockReturnValue({ ...user });
+
+    const propsWithTemplateParam = {
+      ...mockedProps,
+      datasource: {
+        ...testQuery,
+        templateParams: JSON.stringify({ my_param: 12 }),
+      },
+    };
+    render(<SaveDatasetModal {...propsWithTemplateParam} />, {
+      useRedux: true,
+    });
+
+    // Do NOT check the "Include Template Parameters" checkbox
+    await setupOverwriteFlow();
+
+    await waitFor(() => {
+      expect(
+        putSpy.mock.calls.some(([req]) =>
+          req.endpoint?.includes('api/v1/dataset/'),
+        ),
+      ).toBe(true);
+    });
+
+    const datasetPutCall = putSpy.mock.calls.find(([req]) =>
+      req.endpoint?.includes('api/v1/dataset/'),
+    )!;
+    const [req] = datasetPutCall;
+    const body = JSON.parse(req.body as string);
+    expect(body.template_params).toBeUndefined();
+
+    putSpy.mockRestore();
+  });
+
   test('clears dataset cache when creating new dataset', async () => {
     const clearDatasetCache = jest.spyOn(
       require('src/utils/cachedSupersetGet'),

superset-frontend/src/SqlLab/components/SaveDatasetModal/index.tsx

@@ -149,14 +149,25 @@ const Styles = styled.div`
     }
   `}
 `;
-const updateDataset = async (
-  dbId: number,
-  datasetId: number,
-  sql: string,
-  columns: Array<Record<string, any>>,
-  owners: [number],
-  overrideColumns: boolean,
-) => {
+type UpdateDatasetPayload = {
+  dbId: number;
+  datasetId: number;
+  sql: string;
+  columns: Array<Record<string, any>>;
+  owners: number[];
+  overrideColumns: boolean;
+  templateParams?: string;
+};
+
+const updateDataset = async ({
+  dbId,
+  datasetId,
+  sql,
+  columns,
+  owners,
+  overrideColumns,
+  templateParams,
+}: UpdateDatasetPayload) => {
   const endpoint = `api/v1/dataset/${datasetId}?override_columns=${overrideColumns}`;
   const headers = { 'Content-Type': 'application/json' };
   const body = JSON.stringify({
@@ -164,6 +175,7 @@ const updateDataset = async (
     columns,
     owners,
     database_id: dbId,
+    ...(templateParams !== undefined && { template_params: templateParams }),
   });
 
   const data: JsonResponse = await SupersetClient.put({
@@ -179,6 +191,26 @@ const updateDataset = async (
 
 const UNTITLED = t('Untitled Dataset');
 
+// The filters param is only used to test jinja templates.
+// Remove the special filters entry from the templateParams
+// before saving the dataset.
+const sanitizeTemplateParams = (
+  templateParams: string | object | null | undefined,
+): string | undefined => {
+  if (typeof templateParams !== 'string') {
+    return undefined;
+  }
+  try {
+    const parsed = JSON.parse(templateParams) as Record<string, unknown>;
+    // Remove the special _filters entry — it is only used to test jinja templates.
+    const { _filters: _ignored, ...clean } = parsed;
+    return JSON.stringify(clean);
+  } catch (e) {
+    // malformed templateParams, do not include it
+    return undefined;
+  }
+};
+
 export const SaveDatasetModal = ({
   visible,
   onHide,
@@ -232,22 +264,27 @@ export const SaveDatasetModal = ({
     }
     setLoading(true);
 
+    const templateParams = includeTemplateParameters
+      ? sanitizeTemplateParams(datasource?.templateParams)
+      : undefined;
+
     try {
       const [, key] = await Promise.all([
-        updateDataset(
-          datasource?.dbId,
-          datasetToOverwrite?.datasetid,
-          datasource?.sql,
-          datasource?.columns?.map(
+        updateDataset({
+          dbId: datasource?.dbId,
+          datasetId: datasetToOverwrite?.datasetid,
+          sql: datasource?.sql,
+          columns: datasource?.columns?.map(
             (d: { column_name: string; type: string; is_dttm: boolean }) => ({
               column_name: d.column_name,
               type: d.type,
               is_dttm: d.is_dttm,
             }),
           ),
-          datasetToOverwrite?.owners?.map((o: DatasetOwner) => o.id),
-          true,
-        ),
+          owners: datasetToOverwrite?.owners?.map((o: DatasetOwner) => o.id),
+          overrideColumns: true,
+          templateParams,
+        }),
         postFormData(datasetToOverwrite.datasetid, 'table', {
           ...formDataWithDefaults,
           datasource: `${datasetToOverwrite.datasetid}__table`,
@@ -319,27 +356,9 @@ export const SaveDatasetModal = ({
     setLoading(true);
     const selectedColumns = datasource?.columns ?? [];
 
-    // The filters param is only used to test jinja templates.
-    // Remove the special filters entry from the templateParams
-    // before saving the dataset.
-    let templateParams;
-    if (
-      typeof datasource?.templateParams === 'string' &&
-      includeTemplateParameters
-    ) {
-      try {
-        const p = JSON.parse(datasource.templateParams);
-        /* eslint-disable-next-line no-underscore-dangle */
-        if (p._filters) {
-          /* eslint-disable-next-line no-underscore-dangle */
-          delete p._filters;
-        }
-        templateParams = JSON.stringify(p);
-      } catch (e) {
-        // malformed templateParams, do not include it
-        templateParams = undefined;
-      }
-    }
+    const templateParams = includeTemplateParameters
+      ? sanitizeTemplateParams(datasource?.templateParams)
+      : undefined;
 
     dispatch(
       createDatasource({

superset-frontend/src/hooks/apiResources/tables.test.ts

@@ -251,7 +251,7 @@ describe('useTables hook', () => {
     fetchMock.get(`glob:*/api/v1/database/${expectDbId}/schemas/*`, {
       result: fakeSchemaApiResult,
     });
-    const { result, waitFor } = renderHook(
+    const { result } = renderHook(
       () =>
         useTables({
           dbId: expectDbId,

superset-frontend/src/views/store.ts

@@ -22,6 +22,11 @@ import {
   createListenerMiddleware,
   StoreEnhancer,
 } from '@reduxjs/toolkit';
+import {
+  useDispatch,
+  useSelector,
+  type TypedUseSelectorHook,
+} from 'react-redux';
 import thunk from 'redux-thunk';
 import { api } from 'src/hooks/apiResources/queryApi';
 import messageToastReducer from 'src/components/MessageToasts/reducers';
@@ -177,3 +182,12 @@ export function setupStore({
 
 export const store = setupStore();
 export type RootState = ReturnType<typeof store.getState>;
+
+// Typed Redux hooks. Prefer these over the raw `useDispatch` / `useSelector`
+// from react-redux: `useAppDispatch` understands the store's middleware (so
+// thunks resolve correctly), and `useAppSelector` infers `RootState` without
+// callers having to annotate every selector. Required ahead of the
+// react-redux v8+ bump, which tightens dispatch typing — see #39927.
+export type AppDispatch = typeof store.dispatch;
+export const useAppDispatch: () => AppDispatch = useDispatch;
+export const useAppSelector: TypedUseSelectorHook<RootState> = useSelector;

superset/commands/importers/v1/assets.py

@@ -49,8 +49,9 @@ from superset.datasets.schemas import ImportV1DatasetSchema
 from superset.extensions import feature_flag_manager
 from superset.migrations.shared.native_filters import migrate_dashboard
 from superset.models.core import Database
-from superset.models.dashboard import dashboard_slices
+from superset.models.dashboard import Dashboard, dashboard_slices
 from superset.models.slice import Slice
+from superset.models.sql_lab import SavedQuery
 from superset.queries.saved_queries.schemas import ImportV1SavedQuerySchema
 from superset.utils.decorators import on_error, transaction
 
@@ -89,6 +90,9 @@ class ImportAssetsCommand(BaseCommand):
         )
         self._configs: dict[str, Any] = {}
         self.sparse = kwargs.get("sparse", False)
+        # Defaults to ``True`` for backwards compatibility: historically this
+        # command always overwrote existing assets.
+        self.overwrite: bool = kwargs.get("overwrite", True)
 
     # pylint: disable=too-many-locals
     @staticmethod
@@ -96,6 +100,7 @@ class ImportAssetsCommand(BaseCommand):
         configs: dict[str, Any],
         sparse: bool = False,
         contents: Optional[dict[str, Any]] = None,
+        overwrite: bool = True,
     ) -> None:
         contents = {} if contents is None else contents
         # import databases first
@@ -116,20 +121,20 @@ class ImportAssetsCommand(BaseCommand):
 
         for file_name, config in configs.items():
             if file_name.startswith("databases/"):
-                database = import_database(config, overwrite=True)
+                database = import_database(config, overwrite=overwrite)
                 database_ids[str(database.uuid)] = database.id
 
         # import saved queries
         for file_name, config in configs.items():
             if file_name.startswith("queries/"):
                 config["db_id"] = database_ids[config["database_uuid"]]
-                import_saved_query(config, overwrite=True)
+                import_saved_query(config, overwrite=overwrite)
 
         # import datasets
         for file_name, config in configs.items():
             if file_name.startswith("datasets/"):
                 config["database_id"] = database_ids[config["database_uuid"]]
-                dataset = import_dataset(config, overwrite=True)
+                dataset = import_dataset(config, overwrite=overwrite)
                 dataset_info[str(dataset.uuid)] = {
                     "datasource_id": dataset.id,
                     "datasource_type": dataset.datasource_type,
@@ -142,7 +147,7 @@ class ImportAssetsCommand(BaseCommand):
             if file_name.startswith("charts/"):
                 dataset_dict = dataset_info[config["dataset_uuid"]]
                 config = update_chart_config_dataset(config, dataset_dict)
-                chart = import_chart(config, overwrite=True)
+                chart = import_chart(config, overwrite=overwrite)
                 charts.append(chart)
                 chart_ids[str(chart.uuid)] = chart.id
 
@@ -157,7 +162,7 @@ class ImportAssetsCommand(BaseCommand):
         for file_name, config in configs.items():
             if file_name.startswith("dashboards/"):
                 config = update_id_refs(config, chart_ids, dataset_info)
-                dashboard = import_dashboard(config, overwrite=True)
+                dashboard = import_dashboard(config, overwrite=overwrite)
 
                 # set ref in the dashboard_slices table
                 dashboard_chart_ids: list[dict[str, int]] = []
@@ -206,7 +211,73 @@ class ImportAssetsCommand(BaseCommand):
     )
     def run(self) -> None:
         self.validate()
-        self._import(self._configs, self.sparse, self.contents)
+        self._import(self._configs, self.sparse, self.contents, self.overwrite)
+
+    # Maps asset file prefixes to the model class used to look up UUIDs for
+    # the "already exists" validation check when ``overwrite`` is ``False``.
+    _MODEL_BY_PREFIX: dict[str, Any] = {
+        "databases/": Database,
+        "datasets/": SqlaTable,
+        "charts/": Slice,
+        "dashboards/": Dashboard,
+        "queries/": SavedQuery,
+    }
+
+    def _bundle_entries_by_prefix(self) -> dict[str, list[tuple[str, str]]]:
+        """Group ``(file_name, uuid)`` pairs from the bundle by asset prefix."""
+        bundle_by_prefix: dict[str, list[tuple[str, str]]] = {
+            prefix: [] for prefix in self._MODEL_BY_PREFIX
+        }
+        for file_name, config in self._configs.items():
+            uuid = config.get("uuid")
+            if not uuid:
+                continue
+            for prefix in bundle_by_prefix:
+                if file_name.startswith(prefix):
+                    bundle_by_prefix[prefix].append((file_name, str(uuid)))
+                    break
+        return bundle_by_prefix
+
+    def _prevent_overwrite_existing_assets(
+        self, exceptions: list[ValidationError]
+    ) -> None:
+        """
+        When ``overwrite`` is ``False``, raise a clear validation error for any
+        asset in the bundle whose UUID already exists in the database.
+
+        Only the UUIDs present in the import bundle are queried (per prefix),
+        so the cost scales with the bundle size rather than with the total
+        number of stored assets.
+        """
+        if self.overwrite:
+            return
+
+        for prefix, entries in self._bundle_entries_by_prefix().items():
+            if not entries:
+                continue
+            model_cls = self._MODEL_BY_PREFIX[prefix]
+            incoming_uuids = [uuid for _, uuid in entries]
+            existing_uuids = {
+                str(uuid)
+                for (uuid,) in db.session.query(model_cls.uuid)
+                .filter(model_cls.uuid.in_(incoming_uuids))
+                .all()
+            }
+            if not existing_uuids:
+                continue
+            model_name = model_cls.__name__
+            for file_name, uuid in entries:
+                if uuid in existing_uuids:
+                    exceptions.append(
+                        ValidationError(
+                            {
+                                file_name: (
+                                    f"{model_name} already exists "
+                                    "and `overwrite=true` was not passed"
+                                ),
+                            }
+                        )
+                    )
 
     def validate(self) -> None:
         exceptions: list[ValidationError] = []
@@ -229,6 +300,7 @@ class ImportAssetsCommand(BaseCommand):
             self.ssh_tunnel_priv_key_passwords,
             self.encrypted_extra_secrets,
         )
+        self._prevent_overwrite_existing_assets(exceptions)
 
         if exceptions:
             raise CommandInvalidError(

superset/importexport/api.py

@@ -30,6 +30,7 @@ from superset.commands.importers.v1.assets import ImportAssetsCommand
 from superset.commands.importers.v1.utils import get_contents_from_bundle
 from superset.extensions import event_logger
 from superset.utils import json
+from superset.utils.core import parse_boolean_string
 from superset.views.base_api import BaseSupersetApi, requires_form_data, statsd_metrics
 
 
@@ -157,6 +158,12 @@ class ImportExportRestApi(BaseSupersetApi):
                     sparse:
                       description: allow sparse update of resources
                       type: boolean
+                    overwrite:
+                      description: >-
+                        overwrite existing assets? Defaults to ``true`` for
+                        backwards compatibility. When ``false``, the import
+                        fails if any of the assets already exist.
+                      type: boolean
           responses:
             200:
               description: Assets import result
@@ -188,6 +195,9 @@ class ImportExportRestApi(BaseSupersetApi):
         if not contents:
             raise NoValidFilesFoundError()
         sparse = request.form.get("sparse") == "true"
+        # Defaults to True for backwards compatibility: historically this
+        # endpoint always overwrote existing assets.
+        overwrite = parse_boolean_string(request.form.get("overwrite", "true"))
 
         passwords = (
             json.loads(request.form["passwords"])
@@ -218,6 +228,7 @@ class ImportExportRestApi(BaseSupersetApi):
         command = ImportAssetsCommand(
             contents,
             sparse=sparse,
+            overwrite=overwrite,
             passwords=passwords,
             ssh_tunnel_passwords=ssh_tunnel_passwords,
             ssh_tunnel_private_keys=ssh_tunnel_private_keys,

tests/unit_tests/commands/importers/v1/assets_test.py

@@ -19,6 +19,7 @@ import copy
 from typing import Any, cast
 
 import yaml
+from marshmallow.exceptions import ValidationError
 from pytest_mock import MockerFixture
 from sqlalchemy.orm.session import Session
 from sqlalchemy.sql import select
@@ -32,6 +33,18 @@ from tests.unit_tests.fixtures.assets_configs import (
     datasets_config,
 )
 
+saved_queries_config: dict[str, Any] = {
+    "queries/examples/my_query.yaml": {
+        "schema": "main",
+        "label": "My saved query",
+        "description": None,
+        "sql": "SELECT 1",
+        "uuid": "e3e4f1f0-5c9d-4a4c-a4e4-0000000000aa",
+        "version": "1.0.0",
+        "database_uuid": "a2dc77af-e654-49bb-b321-40f6b559a1ee",
+    },
+}
+
 
 def test_import_new_assets(mocker: MockerFixture, session: Session) -> None:
     """
@@ -227,6 +240,309 @@ def test_import_assets_skips_tags_when_feature_disabled(
     assert db.session.query(TaggedObject).count() == 0
 
 
+def test_import_overwrite_defaults_to_true(session: Session) -> None:
+    """
+    ``ImportAssetsCommand.overwrite`` defaults to ``True`` for backwards
+    compatibility — historically the command always overwrote existing assets.
+    """
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+
+    command = ImportAssetsCommand({})
+    assert command.overwrite is True
+
+    explicit_false = ImportAssetsCommand({}, overwrite=False)
+    assert explicit_false.overwrite is False
+
+
+def test_import_threads_overwrite_flag(mocker: MockerFixture, session: Session) -> None:
+    """
+    ``overwrite`` must be threaded through to ``import_database``,
+    ``import_saved_query``, ``import_dataset``, ``import_chart`` and
+    ``import_dashboard``. Previously these were hard-coded to ``overwrite=True``
+    which caused the API flag to be ignored.
+    """
+    from superset import security_manager
+    from superset.commands.importers.v1 import assets as assets_module
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+
+    mocker.patch.object(security_manager, "can_access", return_value=True)
+
+    mocked_db = mocker.patch.object(assets_module, "import_database")
+    mocked_db.return_value.uuid = "a2dc77af-e654-49bb-b321-40f6b559a1ee"
+    mocked_db.return_value.id = 1
+    mocked_ds = mocker.patch.object(assets_module, "import_dataset")
+    mocked_ds.return_value.uuid = "53d47c0c-c03d-47f0-b9ac-81225f808283"
+    mocked_ds.return_value.id = 1
+    mocked_ds.return_value.datasource_type = "table"
+    mocked_ds.return_value.table_name = "video_game_sales"
+    mocked_chart = mocker.patch.object(assets_module, "import_chart")
+    mocked_chart.return_value.viz_type = "table"
+    mocked_dash = mocker.patch.object(assets_module, "import_dashboard")
+    mocker.patch.object(assets_module, "find_chart_uuids", return_value=[])
+    mocker.patch.object(assets_module, "update_id_refs", side_effect=lambda c, *_: c)
+    mocker.patch.object(assets_module, "migrate_dashboard")
+    mocker.patch("superset.db.session.execute")
+
+    configs = {
+        **copy.deepcopy(databases_config),
+        **copy.deepcopy(datasets_config),
+        **copy.deepcopy(charts_config_1),
+        **copy.deepcopy(dashboards_config_1),
+    }
+
+    ImportAssetsCommand._import(configs, overwrite=False)
+
+    assert mocked_db.called
+    for call in mocked_db.call_args_list:
+        assert call.kwargs["overwrite"] is False
+    for call in mocked_ds.call_args_list:
+        assert call.kwargs["overwrite"] is False
+    for call in mocked_chart.call_args_list:
+        assert call.kwargs["overwrite"] is False
+    for call in mocked_dash.call_args_list:
+        assert call.kwargs["overwrite"] is False
+
+
+def test_prevent_overwrite_flags_existing_assets(
+    mocker: MockerFixture, session: Session
+) -> None:
+    """
+    With ``overwrite=False``, ``_prevent_overwrite_existing_assets`` must
+    surface a clear ``ValidationError`` for each asset whose UUID already
+    exists in the database.
+    """
+    from superset import db, security_manager
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+    from superset.models.slice import Slice
+
+    mocker.patch.object(security_manager, "can_access", return_value=True)
+    engine = db.session.get_bind()
+    Slice.metadata.create_all(engine)  # pylint: disable=no-member
+
+    # seed the database with the fixture assets
+    seed_configs = {
+        **copy.deepcopy(databases_config),
+        **copy.deepcopy(datasets_config),
+        **copy.deepcopy(charts_config_1),
+        **copy.deepcopy(dashboards_config_1),
+    }
+    ImportAssetsCommand._import(seed_configs)
+
+    command = ImportAssetsCommand({}, overwrite=False)
+    command._configs = {
+        **copy.deepcopy(databases_config),
+        **copy.deepcopy(datasets_config),
+        **copy.deepcopy(charts_config_1),
+        **copy.deepcopy(dashboards_config_1),
+    }
+
+    exceptions: list[ValidationError] = []
+    command._prevent_overwrite_existing_assets(exceptions)
+
+    # one exception for each of the seeded assets (db + datasets + charts + dashboards)
+    expected_count = (
+        len(databases_config)
+        + len(datasets_config)
+        + len(charts_config_1)
+        + len(dashboards_config_1)
+    )
+    assert len(exceptions) == expected_count
+    for exc in exceptions:
+        assert isinstance(exc, ValidationError)
+        [(_, message)] = exc.messages.items()
+        assert "already exists" in message
+        assert "`overwrite=true` was not passed" in message
+
+
+def test_prevent_overwrite_allows_new_assets(
+    mocker: MockerFixture, session: Session
+) -> None:
+    """
+    With ``overwrite=False`` and no conflicting UUIDs in the database, the
+    validation step must not raise.
+    """
+    from superset import db, security_manager
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+    from superset.models.slice import Slice
+
+    mocker.patch.object(security_manager, "can_access", return_value=True)
+    engine = db.session.get_bind()
+    Slice.metadata.create_all(engine)  # pylint: disable=no-member
+
+    command = ImportAssetsCommand({}, overwrite=False)
+    command._configs = {
+        **copy.deepcopy(databases_config),
+        **copy.deepcopy(datasets_config),
+        **copy.deepcopy(charts_config_1),
+        **copy.deepcopy(dashboards_config_1),
+    }
+
+    exceptions: list[ValidationError] = []
+    command._prevent_overwrite_existing_assets(exceptions)
+
+    assert exceptions == []
+
+
+def test_prevent_overwrite_noop_when_overwrite_true(
+    mocker: MockerFixture, session: Session
+) -> None:
+    """
+    With ``overwrite=True`` (the default) the "already exists" validation must
+    be a no-op even when assets exist in the database — this preserves the
+    historical behavior.
+    """
+    from superset import db, security_manager
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+    from superset.models.slice import Slice
+
+    mocker.patch.object(security_manager, "can_access", return_value=True)
+    engine = db.session.get_bind()
+    Slice.metadata.create_all(engine)  # pylint: disable=no-member
+
+    seed_configs = {
+        **copy.deepcopy(databases_config),
+        **copy.deepcopy(datasets_config),
+        **copy.deepcopy(charts_config_1),
+        **copy.deepcopy(dashboards_config_1),
+    }
+    ImportAssetsCommand._import(seed_configs)
+
+    command = ImportAssetsCommand({})  # overwrite defaults to True
+    command._configs = copy.deepcopy(seed_configs)
+
+    exceptions: list[ValidationError] = []
+    command._prevent_overwrite_existing_assets(exceptions)
+
+    assert exceptions == []
+
+
+def test_prevent_overwrite_flags_existing_saved_queries(
+    mocker: MockerFixture, session: Session
+) -> None:
+    """
+    Saved queries (``queries/`` prefix) must also be covered by the
+    "already exists" validation when ``overwrite=False`` — otherwise
+    ``import_saved_query`` silently returns existing rows and the endpoint
+    would appear to succeed despite the conflict.
+    """
+    from superset import db, security_manager
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+    from superset.models.slice import Slice
+    from superset.models.sql_lab import SavedQuery
+
+    mocker.patch.object(security_manager, "can_access", return_value=True)
+    engine = db.session.get_bind()
+    Slice.metadata.create_all(engine)  # pylint: disable=no-member
+    SavedQuery.metadata.create_all(engine)  # pylint: disable=no-member
+
+    # seed a saved query with a UUID that matches the fixture below
+    saved_query_uuid = next(iter(saved_queries_config.values()))["uuid"]
+    db.session.add(SavedQuery(uuid=saved_query_uuid, label="seeded"))
+    db.session.flush()
+
+    command = ImportAssetsCommand({}, overwrite=False)
+    command._configs = copy.deepcopy(saved_queries_config)
+
+    exceptions: list[ValidationError] = []
+    command._prevent_overwrite_existing_assets(exceptions)
+
+    assert len(exceptions) == 1
+    [(file_name, message)] = exceptions[0].messages.items()
+    assert file_name.startswith("queries/")
+    assert "SavedQuery already exists" in message
+
+
+def test_prevent_overwrite_partial_conflict(
+    mocker: MockerFixture, session: Session
+) -> None:
+    """
+    When only some of the incoming assets already exist, validation must flag
+    exactly the conflicting ones and leave brand-new assets untouched.
+    """
+    from superset import db, security_manager
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+    from superset.models.slice import Slice
+
+    mocker.patch.object(security_manager, "can_access", return_value=True)
+    engine = db.session.get_bind()
+    Slice.metadata.create_all(engine)  # pylint: disable=no-member
+
+    # seed only databases + datasets; charts and dashboards stay new
+    ImportAssetsCommand._import(
+        {
+            **copy.deepcopy(databases_config),
+            **copy.deepcopy(datasets_config),
+        }
+    )
+
+    command = ImportAssetsCommand({}, overwrite=False)
+    command._configs = {
+        **copy.deepcopy(databases_config),
+        **copy.deepcopy(datasets_config),
+        **copy.deepcopy(charts_config_1),
+        **copy.deepcopy(dashboards_config_1),
+    }
+
+    exceptions: list[ValidationError] = []
+    command._prevent_overwrite_existing_assets(exceptions)
+
+    flagged_files = {next(iter(exc.messages)) for exc in exceptions}
+    assert flagged_files == set(databases_config) | set(datasets_config)
+
+
+def test_prevent_overwrite_queries_only_bundle_uuids(
+    mocker: MockerFixture, session: Session
+) -> None:
+    """
+    The validation must scope its UUID lookup to the UUIDs present in the
+    import bundle (one ``WHERE uuid IN (...)`` query per prefix that has
+    incoming entries) and skip prefixes with no entries entirely. Otherwise
+    every import with ``overwrite=false`` would scan all asset tables in
+    full, regardless of bundle size.
+    """
+    from superset import db, security_manager
+    from superset.commands.importers.v1.assets import ImportAssetsCommand
+    from superset.connectors.sqla.models import SqlaTable
+    from superset.models.core import Database
+    from superset.models.dashboard import Dashboard
+    from superset.models.slice import Slice
+    from superset.models.sql_lab import SavedQuery
+
+    mocker.patch.object(security_manager, "can_access", return_value=True)
+    engine = db.session.get_bind()
+    Slice.metadata.create_all(engine)  # pylint: disable=no-member
+    SavedQuery.metadata.create_all(engine)  # pylint: disable=no-member
+
+    # bundle only contains a database — no datasets/charts/dashboards/queries
+    bundle = copy.deepcopy(databases_config)
+
+    spy = mocker.spy(db.session, "query")
+
+    command = ImportAssetsCommand({}, overwrite=False)
+    command._configs = bundle
+    exceptions: list[ValidationError] = []
+    command._prevent_overwrite_existing_assets(exceptions)
+
+    # exactly one UUID query — for the only prefix with bundle entries — and
+    # it targets the Database UUID column. Empty-bundle prefixes (datasets/
+    # charts/dashboards/queries) must not be queried at all, otherwise this
+    # validation degrades to a full-table scan per asset type.
+    queried_columns = [
+        call.args[0]
+        for call in spy.call_args_list
+        if call.args and getattr(call.args[0], "key", None) == "uuid"
+    ]
+    assert len(queried_columns) == 1
+    assert queried_columns[0].class_ is Database
+
+    queried_models = {col.class_ for col in queried_columns}
+    for model_cls in (SqlaTable, Slice, Dashboard, SavedQuery):
+        assert model_cls not in queried_models
+
+    # no row matches in an empty table, so no validation errors are raised
+    assert exceptions == []
+
+
 def test_import_removes_dashboard_charts(
     mocker: MockerFixture, session: Session
 ) -> None:

tests/unit_tests/importexport/api_test.py

@@ -48,7 +48,9 @@ def test_export_assets(
     mocked_export_result = [
         (
             "metadata.yaml",
-            lambda: "version: 1.0.0\ntype: assets\ntimestamp: '2022-01-01T00:00:00+00:00'\n",  # noqa: E501
+            lambda: (
+                "version: 1.0.0\ntype: assets\ntimestamp: '2022-01-01T00:00:00+00:00'\n"
+            ),  # noqa: E501
         ),
         ("databases/example.yaml", lambda: "<DATABASE CONTENTS>"),
     ]
@@ -109,6 +111,7 @@ def test_import_assets(
     ImportAssetsCommand.assert_called_with(
         mocked_contents,
         sparse=False,
+        overwrite=True,
         passwords=passwords,
         ssh_tunnel_passwords=None,
         ssh_tunnel_private_keys=None,
@@ -160,6 +163,7 @@ def test_import_assets_with_encrypted_extra_secrets(
     ImportAssetsCommand.assert_called_with(
         mocked_contents,
         sparse=False,
+        overwrite=True,
         passwords=None,
         ssh_tunnel_passwords=None,
         ssh_tunnel_private_keys=None,
@@ -168,6 +172,54 @@ def test_import_assets_with_encrypted_extra_secrets(
     )
 
 
+def test_import_assets_overwrite_false(
+    mocker: MockerFixture,
+    client: Any,
+    full_api_access: None,
+) -> None:
+    """
+    Passing ``overwrite=false`` on the form must be forwarded to
+    ``ImportAssetsCommand``. Previously the flag was ignored and assets were
+    always overwritten.
+    """
+    mocked_contents = {
+        "metadata.yaml": (
+            "version: 1.0.0\ntype: assets\ntimestamp: '2022-01-01T00:00:00+00:00'\n"
+        ),
+        "databases/example.yaml": "<DATABASE CONTENTS>",
+    }
+
+    ImportAssetsCommand = mocker.patch("superset.importexport.api.ImportAssetsCommand")  # noqa: N806
+
+    root = Path("assets_export")
+    buf = BytesIO()
+    with ZipFile(buf, "w") as bundle:
+        for path, contents in mocked_contents.items():
+            with bundle.open(str(root / path), "w") as fp:
+                fp.write(contents.encode())
+    buf.seek(0)
+
+    form_data = {
+        "bundle": (buf, "assets_export.zip"),
+        "overwrite": "false",
+    }
+    response = client.post(
+        "/api/v1/assets/import/", data=form_data, content_type="multipart/form-data"
+    )
+    assert response.status_code == 200
+
+    ImportAssetsCommand.assert_called_with(
+        mocked_contents,
+        sparse=False,
+        overwrite=False,
+        passwords=None,
+        ssh_tunnel_passwords=None,
+        ssh_tunnel_private_keys=None,
+        ssh_tunnel_priv_key_passwords=None,
+        encrypted_extra_secrets=None,
+    )
+
+
 def test_import_assets_not_zip(
     mocker: MockerFixture,
     client: Any,