Fix lint

superset-frontend/src/components/Chart/DrillDetail/DrillDetailPane.test.tsx

@@ -221,6 +221,12 @@ test('should render the error', async () => {
     .spyOn(SupersetClient, 'post')
     .mockRejectedValue(new Error('Something went wrong'));
   await waitForRender();
+  // The error is wrapped in an Alert component with a stable headline and the
+  // raw error text in the description — no more bare ``<pre>`` elements.
+  expect(await screen.findByRole('alert')).toBeVisible();
+  expect(
+    await screen.findByText('Failed to load drill-to-detail rows'),
+  ).toBeVisible();
   expect(screen.getByText('Error: Something went wrong')).toBeInTheDocument();
 });
 

superset-frontend/src/components/Chart/DrillDetail/DrillDetailPane.tsx

@@ -42,6 +42,7 @@ import BooleanCell from '@superset-ui/core/components/Table/cell-renderers/Boole
 import NullCell from '@superset-ui/core/components/Table/cell-renderers/NullCell';
 import TimeCell from '@superset-ui/core/components/Table/cell-renderers/TimeCell';
 import { EmptyState, Loading } from '@superset-ui/core/components';
+import { Alert } from '@apache-superset/core/components';
 import { getDatasourceSamples } from 'src/components/Chart/chartAction';
 import Table, {
   ColumnsType,
@@ -362,13 +363,18 @@ export default function DrillDetailPane({
   if (responseError) {
     // Render error if page download failed
     tableContent = (
-      <pre
+      <div
         css={css`
           margin-top: ${theme.sizeUnit * 4}px;
         `}
       >
-        {responseError}
+        <Alert
-      </pre>
+          type="error"
+          showIcon
+          message={t('Failed to load drill-to-detail rows')}
+          description={responseError}
+        />
+      </div>
     );
   } else if (bootstrapping) {
     // Render loading if first page hasn't loaded

superset-frontend/src/components/Chart/useDrillDetailMenuItems/index.tsx

@@ -50,6 +50,7 @@ const DISABLED_REASONS = {
   DATABASE: t(
     'Drill to detail is disabled for this database. Change the database settings to enable it.',
   ),
+  DATASOURCE: t('Drill to detail is not available for this datasource type.'),
   NO_AGGREGATIONS: t(
     'Drill to detail is disabled because this chart does not group data by dimension value.',
   ),
@@ -116,6 +117,17 @@ export const useDrillDetailMenuItems = ({
       datasources[formData.datasource]?.database?.disable_drill_to_detail,
   );
 
+  // Capability flag on the datasource itself. Datasources that don't model
+  // raw rows (e.g. semantic views) opt out via ``supports_drill_to_detail``
+  // in the explore data payload.
+  const datasourceSupportsDrillToDetail = useSelector<
+    RootState,
+    boolean | undefined
+  >(
+    ({ datasources }) =>
+      datasources[formData.datasource]?.supports_drill_to_detail,
+  );
+
   const openModal = useCallback(
     (filters: BinaryQueryObjectFilterClause[], event: MouseEvent) => {
       onClick(event);
@@ -158,7 +170,10 @@ export const useDrillDetailMenuItems = ({
 
   let drillDisabled;
   let drillByDisabled;
-  if (drillToDetailDisabled) {
+  if (datasourceSupportsDrillToDetail === false) {
+    drillDisabled = DISABLED_REASONS.DATASOURCE;
+    drillByDisabled = DISABLED_REASONS.DATASOURCE;
+  } else if (drillToDetailDisabled) {
     drillDisabled = DISABLED_REASONS.DATABASE;
     drillByDisabled = DISABLED_REASONS.DATABASE;
   } else if (handlesDimensionContextMenu) {

superset-frontend/src/components/Chart/useDrillDetailMenuItems/useDrillDetailMenuItems.test.tsx

@@ -444,3 +444,45 @@ test('context menu renders <NULL> for null dimension values', async () => {
   await expectDrillToDetailByEnabled();
   await expectDrillToDetailByDimension(filterNull);
 });
+
+const buildStateWithUnsupportedDatasource = () => {
+  const baseState = getMockStoreWithNativeFilters().getState();
+  const datasourceKey = defaultFormData.datasource as string;
+  return {
+    ...baseState,
+    datasources: {
+      ...baseState.datasources,
+      [datasourceKey]: {
+        ...baseState.datasources[datasourceKey],
+        supports_drill_to_detail: false,
+      },
+    },
+  };
+};
+
+test('dropdown menu when datasource opts out via supports_drill_to_detail=false', async () => {
+  cleanup();
+  render(<MockRenderChart formData={defaultFormData} />, {
+    useRouter: true,
+    useRedux: true,
+    initialState: buildStateWithUnsupportedDatasource(),
+  });
+
+  await expectDrillToDetailDisabled(
+    'Drill to detail is not available for this datasource type.',
+  );
+  await expectNoDrillToDetailBy();
+});
+
+test('context menu when datasource opts out via supports_drill_to_detail=false', async () => {
+  cleanup();
+  render(<MockRenderChart formData={defaultFormData} isContextMenu />, {
+    useRouter: true,
+    useRedux: true,
+    initialState: buildStateWithUnsupportedDatasource(),
+  });
+
+  const message = 'Drill to detail is not available for this datasource type.';
+  await expectDrillToDetailDisabled(message);
+  await expectDrillToDetailByDisabled(message);
+});

superset-frontend/src/components/GridTable/Header.test.tsx

@@ -210,7 +210,11 @@ test('does not attach click handler when enableSorting is false', () => {
 test('does not call progressSort on click when enableSorting is false', () => {
   const progressSort = jest.fn();
   const { getByText } = render(
-    <Header {...mockedProps} enableSorting={false} progressSort={progressSort} />,
+    <Header
+      {...mockedProps}
+      enableSorting={false}
+      progressSort={progressSort}
+    />,
   );
   fireEvent.click(getByText(mockedProps.displayName));
   expect(progressSort).not.toHaveBeenCalled();

superset-frontend/src/dashboard/types.ts

@@ -231,6 +231,10 @@ export type Datasource = Dataset & {
   column_types: GenericDataType[];
   table_name: string;
   database?: Database;
+  /** False when the datasource can't return row samples (e.g. semantic views). */
+  supports_samples?: boolean;
+  /** False when the datasource can't answer drill-to-detail requests. */
+  supports_drill_to_detail?: boolean;
 };
 export type DatasourcesState = {
   [key: string]: Datasource;

superset-frontend/src/explore/components/DataTablesPane/DataTablesPane.tsx

@@ -234,25 +234,44 @@ export const DataTablesPane = ({
     }
   }, [resultsTabFallback]);
 
+  // Hide the Samples tab for datasources that don't expose raw rows
+  // (e.g. semantic views). The check is intentionally ``=== false`` so that
+  // datasources from older backends that don't send the flag still show the
+  // tab and preserve current behavior.
+  const showSamplesTab = datasource?.supports_samples !== false;
+
+  // If the datasource swaps to one that doesn't support samples while the
+  // Samples tab is active (e.g. the user picks a semantic view), the tab
+  // disappears from ``tabItems`` and ``activeTabKey`` is orphaned. Fall back
+  // to Results so the panel keeps rendering content.
+  useEffect(() => {
+    if (!showSamplesTab && activeTabKey === ResultTypes.Samples) {
+      setActiveTabKey(ResultTypes.Results);
+    }
+  }, [showSamplesTab, activeTabKey]);
   const tabItems = [
     ...queryResultsPanes,
-    {
+    ...(showSamplesTab
-      key: ResultTypes.Samples,
+      ? [
-      label: t('Samples'),
+          {
-      children: (
+            key: ResultTypes.Samples,
-        <StyledDiv>
+            label: t('Samples'),
-          <SamplesPane
+            children: (
-            datasource={datasource}
+              <StyledDiv>
-            queryFormData={queryFormData}
+                <SamplesPane
-            queryForce={queryForce}
+                  datasource={datasource}
-            isRequest={isRequest.samples}
+                  queryFormData={queryFormData}
-            setForceQuery={setForceQuery}
+                  queryForce={queryForce}
-            isVisible={ResultTypes.Samples === activeTabKey}
+                  isRequest={isRequest.samples}
-            canDownload={canDownload}
+                  setForceQuery={setForceQuery}
-          />
+                  isVisible={ResultTypes.Samples === activeTabKey}
-        </StyledDiv>
+                  canDownload={canDownload}
-      ),
+                />
-    },
+              </StyledDiv>
+            ),
+          },
+        ]
+      : []),
   ];
 
   return (

superset-frontend/src/explore/components/DataTablesPane/components/SamplesPane.tsx

@@ -21,6 +21,7 @@ import { t } from '@apache-superset/core/translation';
 import { ensureIsArray } from '@superset-ui/core';
 import { datasetLabelLower } from 'src/features/semanticLayers/label';
 import { styled } from '@apache-superset/core/theme';
+import { Alert } from '@apache-superset/core/components';
 import { EmptyState, Loading } from '@superset-ui/core/components';
 import { GenericDataType } from '@apache-superset/core/common';
 import { GridTable } from 'src/components/GridTable';
@@ -35,7 +36,7 @@ import {
 import { TableControls, ROW_LIMIT_OPTIONS } from './DataTableControls';
 import { SamplesPaneProps } from '../types';
 
-const Error = styled.pre`
+const ErrorAlertWrapper = styled.div`
   margin-top: ${({ theme }) => `${theme.sizeUnit * 4}px`};
 `;
 
@@ -155,7 +156,14 @@ export const SamplesPane = ({
           rowLimitOptions={ROW_LIMIT_OPTIONS}
           onRowLimitChange={handleRowLimitChange}
         />
-        <Error>{responseError}</Error>
+        <ErrorAlertWrapper>
+          <Alert
+            type="error"
+            showIcon
+            message={t('Failed to load samples')}
+            description={responseError}
+          />
+        </ErrorAlertWrapper>
       </>
     );
   }

superset-frontend/src/explore/components/DataTablesPane/components/useResultsPane.tsx

@@ -27,13 +27,14 @@ import {
   QueryData,
 } from '@superset-ui/core';
 import { styled } from '@apache-superset/core/theme';
+import { Alert } from '@apache-superset/core/components';
 import { EmptyState, Loading } from '@superset-ui/core/components';
 import { getChartDataRequest } from 'src/components/Chart/chartAction';
 import { ResultsPaneProps, QueryResultInterface } from '../types';
 import { SingleQueryResultPane } from './SingleQueryResultPane';
 import { TableControls, ROW_LIMIT_OPTIONS } from './DataTableControls';
 
-const Error = styled.pre`
+const ErrorAlertWrapper = styled.div`
   margin-top: ${({ theme }) => `${theme.sizeUnit * 4}px`};
 `;
 
@@ -199,7 +200,14 @@ export const useResultsPane = ({
           isLoading={false}
           canDownload={canDownload}
         />
-        <Error>{responseError}</Error>
+        <ErrorAlertWrapper>
+          <Alert
+            type="error"
+            showIcon
+            message={t('Failed to load results')}
+            description={responseError}
+          />
+        </ErrorAlertWrapper>
       </>
     );
     return Array(queryCount).fill(err);

superset-frontend/src/explore/components/DataTablesPane/test/DataTablesPane.test.tsx

@@ -19,7 +19,12 @@
 import fetchMock from 'fetch-mock';
 import { FeatureFlag } from '@superset-ui/core';
 import * as copyUtils from 'src/utils/copy';
-import { render, screen, userEvent } from 'spec/helpers/testing-library';
+import {
+  render,
+  screen,
+  userEvent,
+  waitFor,
+} from 'spec/helpers/testing-library';
 import { setupAGGridModules } from '@superset-ui/core/components/ThemedAgGridReact';
 import { setItem, LocalStorageKeys } from 'src/utils/localStorageHelpers';
 import { DataTablesPane } from '..';
@@ -89,6 +94,48 @@ describe('DataTablesPane', () => {
     expect(await screen.findByLabelText('Collapse data panel')).toBeVisible();
   });
 
+  test('Hides Samples tab when datasource opts out via supports_samples=false', async () => {
+    const props = createDataTablesPaneProps(0);
+    const propsWithoutSamples = {
+      ...props,
+      datasource: { ...props.datasource, supports_samples: false },
+    };
+    render(<DataTablesPane {...propsWithoutSamples} />, { useRedux: true });
+    expect(await screen.findByText('Results')).toBeVisible();
+    expect(screen.queryByText('Samples')).not.toBeInTheDocument();
+  });
+
+  test('Falls back to Results when active Samples tab disappears mid-session', async () => {
+    // Regression for codeant Major finding on PR #41509: a datasource swap
+    // that hides the Samples tab while it was the active tab used to leave
+    // ``activeTabKey === 'samples'`` orphaned, rendering a blank panel.
+    const props = createDataTablesPaneProps(0);
+    const { rerender } = render(<DataTablesPane {...props} />, {
+      useRedux: true,
+    });
+
+    // Open the panel and pick the Samples tab.
+    userEvent.click(screen.getByLabelText('Expand data panel'));
+    userEvent.click(await screen.findByText('Samples'));
+    expect(await screen.findByLabelText('Collapse data panel')).toBeVisible();
+
+    // Swap to a datasource that doesn't support samples (e.g. a semantic
+    // view). The Samples tab should disappear and the panel should land on
+    // Results with content still rendered.
+    rerender(
+      <DataTablesPane
+        {...props}
+        datasource={{ ...props.datasource, supports_samples: false }}
+      />,
+    );
+    await waitFor(() => {
+      expect(screen.queryByText('Samples')).not.toBeInTheDocument();
+    });
+    expect(screen.getByText('Results')).toBeVisible();
+    // Panel stays expanded and renders Results content rather than going blank.
+    expect(screen.getByLabelText('Collapse data panel')).toBeVisible();
+  });
+
   test('Should copy data table content correctly', async () => {
     fetchMock.post(
       'glob:*/api/v1/chart/data?form_data=%7B%22slice_id%22%3A456%7D',

superset-frontend/src/explore/components/DataTablesPane/test/SamplesPane.test.tsx

@@ -84,10 +84,14 @@ describe('SamplesPane', () => {
     const props = createSamplesPaneProps({
       datasourceId: 36,
     });
-    const { findByText } = render(<SamplesPane {...props} />, {
+    const { findByText, findByRole } = render(<SamplesPane {...props} />, {
       useRedux: true,
     });
 
+    // The error is now rendered inside an Alert component, with a clear
+    // headline message and the raw error text as the description.
+    expect(await findByRole('alert')).toBeVisible();
+    expect(await findByText('Failed to load samples')).toBeVisible();
     expect(await findByText('Error: Bad request')).toBeVisible();
   });
 

superset-frontend/src/explore/types.ts

@@ -41,11 +41,7 @@ export enum ChartStatusType {
 }
 
 export type ChartStatus =
-  | 'loading'
+  'loading' | 'rendered' | 'failed' | 'stopped' | 'success';
-  | 'rendered'
-  | 'failed'
-  | 'stopped'
-  | 'success';
 
 export interface ChartState {
   id: number;
@@ -78,6 +74,18 @@ export type Datasource = Dataset & {
   schema?: string;
   is_sqllab_view?: boolean;
   extra?: string | object;
+  /**
+   * False when the datasource (e.g. a semantic view) doesn't model raw rows
+   * and therefore can't return a row sample. Defaults to true on the server
+   * side; missing here means the explore UI keeps current behavior.
+   */
+  supports_samples?: boolean;
+  /**
+   * False when the datasource doesn't model raw rows and therefore can't
+   * answer a drill-to-detail query. Tracked separately from
+   * ``supports_samples`` so the two capabilities can diverge.
+   */
+  supports_drill_to_detail?: boolean;
 };
 
 export interface ExplorePageInitialData {

superset-frontend/src/features/alerts/AlertReportModal.test.tsx

@@ -694,7 +694,9 @@ test('open chart button opens explore with slice_id', async () => {
   });
   expect(openChartButton).toBeInTheDocument();
 
-  const navSpy = jest.spyOn(navigationUtils, 'navigateTo').mockImplementation(() => null);
+  const navSpy = jest
+    .spyOn(navigationUtils, 'navigateTo')
+    .mockImplementation(() => null);
   try {
     await userEvent.click(openChartButton);
     expect(navSpy).toHaveBeenCalledWith(
@@ -721,7 +723,9 @@ test('open dashboard button opens dashboard url', async () => {
   });
   expect(openDashButton).toBeInTheDocument();
 
-  const navSpy = jest.spyOn(navigationUtils, 'navigateTo').mockImplementation(() => null);
+  const navSpy = jest
+    .spyOn(navigationUtils, 'navigateTo')
+    .mockImplementation(() => null);
   try {
     await userEvent.click(openDashButton);
     expect(navSpy).toHaveBeenCalledWith(

superset/common/query_actions.py

@@ -230,6 +230,15 @@ def _get_drill_detail(
     # todo(yongjie): Remove this function,
     #  when determining whether samples should be applied to the time filter.
     datasource = _get_datasource(query_context, query_obj)
+    # Refuse for datasource types that don't model raw rows (e.g. semantic
+    # views). Mirrors the ``supports_samples`` gate on the ``/samples``
+    # endpoint so drill-detail is hard-blocked on the backend, not just
+    # hidden in the frontend menu. Defaults to ``True`` for any datasource
+    # class that doesn't explicitly opt out.
+    if not getattr(datasource, "supports_drill_to_detail", True):
+        raise QueryObjectValidationError(
+            _("Drill to detail is not available for this datasource type.")
+        )
     query_obj = copy.copy(query_obj)
     query_obj.is_timeseries = False
     query_obj.metrics = None

superset/connectors/sqla/models.py

@@ -194,6 +194,16 @@ class BaseDatasource(
     # Only some datasources support Row Level Security
     is_rls_supported: bool = False
 
+    # Datasources that can return raw row samples (anything backed by a SQL
+    # table can; semantic-layer abstractions cannot, since they only expose
+    # pre-defined metrics and dimensions).
+    supports_samples: bool = True
+
+    # Datasources that can answer "drill to detail" requests — i.e. fetch the
+    # raw rows underlying a chart cell. Conceptually similar to ``samples``
+    # but kept as a separate capability so the two can diverge.
+    supports_drill_to_detail: bool = True
+
     @property
     def name(self) -> str:
         # can be a Column or a property pointing to one
@@ -501,6 +511,8 @@ class BaseDatasource(
             "owners": [owner.id for owner in self.owners],
             "verbose_map": self.verbose_map,
             "select_star": self.select_star,
+            "supports_samples": self.supports_samples,
+            "supports_drill_to_detail": self.supports_drill_to_detail,
         }
 
     def data_for_slices(  # pylint: disable=too-many-locals  # noqa: C901

superset/semantic_layers/models.py

@@ -196,6 +196,12 @@ class SemanticView(AuditMixinNullable, Model):
 
     __tablename__ = "semantic_views"
 
+    # Semantic views expose pre-defined metrics and dimensions, not raw rows,
+    # so neither the "Samples" tab in Explore nor the "Drill to detail"
+    # affordance from the chart 3-dots menu can return anything meaningful.
+    supports_samples: bool = False
+    supports_drill_to_detail: bool = False
+
     # Use integer as the primary key for cross-database auto-increment
     # compatibility (sa.Identity() is not supported in MySQL or SQLite).
     # The uuid column is a secondary unique identifier used in URLs and perms.
@@ -393,6 +399,8 @@ class SemanticView(AuditMixinNullable, Model):
             "filter_select_enabled": True,
             "sql": None,
             "select_star": None,
+            "supports_samples": self.supports_samples,
+            "supports_drill_to_detail": self.supports_drill_to_detail,
             "owners": [],
             "description": self.description,
             "table_name": self.name,

superset/superset_typing.py

@@ -338,6 +338,11 @@ class ExplorableData(TypedDict, total=False):
     extra: str | None
     always_filter_main_dttm: bool
     normalize_columns: bool
+    # Set by datasources that cannot return raw row samples (e.g. semantic
+    # views, which only expose pre-defined metrics and dimensions).
+    supports_samples: bool
+    # Set by datasources that cannot answer drill-to-detail requests.
+    supports_drill_to_detail: bool
 
 
 VizData: TypeAlias = list[Any] | dict[Any, Any] | None

superset/views/datasource/views.py

@@ -208,6 +208,23 @@ class Datasource(BaseSupersetView):
             payload = SamplesPayloadSchema().load(request.json)
         except ValidationError as err:
             return json_error_response(err.messages, status=400)
+
+        # Refuse early for datasource types that don't model raw rows
+        # (e.g. semantic views, which only expose pre-defined metrics and
+        # dimensions). Without this gate the request would still go through
+        # the standard query pipeline and fail with an opaque 500.
+        # ``supports_samples`` defaults to True for any datasource class that
+        # doesn't explicitly opt out, so SqlaTable/Query/SavedQuery continue
+        # to work without needing the attribute declared on each class.
+        ds_class = DatasourceDAO.sources.get(
+            DatasourceType(params["datasource_type"]),
+        )
+        if ds_class is not None and not getattr(ds_class, "supports_samples", True):
+            return json_error_response(
+                _("Samples are not available for this datasource type."),
+                status=400,
+            )
+
         dashboard_id = None
         if security_manager.is_guest_user():
             if not params["dashboard_id"]:

tests/unit_tests/common/test_query_actions_drill_detail.py

@@ -0,0 +1,70 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from superset.common.query_actions import _get_drill_detail
+from superset.exceptions import QueryObjectValidationError
+
+
+def test_get_drill_detail_refuses_datasource_that_opts_out() -> None:
+    """
+    A datasource with ``supports_drill_to_detail = False`` (e.g. semantic
+    views) must be hard-blocked on the server. Without this gate the request
+    would fall through to ``_get_full`` and fail with an opaque error, and
+    the flag would only be enforced by the frontend menu — leaving the
+    chart-data API endpoint accepting drill-detail requests it shouldn't.
+    """
+    datasource = MagicMock()
+    datasource.supports_drill_to_detail = False
+
+    query_obj = MagicMock()
+    query_obj.datasource = datasource
+
+    query_context = MagicMock()
+
+    with pytest.raises(
+        QueryObjectValidationError,
+        match="Drill to detail is not available",
+    ):
+        _get_drill_detail(query_context, query_obj)
+
+
+def test_get_drill_detail_allows_datasource_without_flag() -> None:
+    """
+    Datasources that don't declare the flag (e.g. legacy ``SqlaTable``
+    subclasses via ``getattr`` default) must continue to work — the gate
+    only fires when the flag is explicitly ``False``.
+    """
+    datasource = MagicMock(spec=["columns"])
+    column = MagicMock()
+    column.column_name = "id"
+    datasource.columns = [column]
+
+    query_obj = MagicMock()
+    query_obj.datasource = datasource
+    query_obj.columns = []
+
+    query_context = MagicMock()
+
+    expected_payload: dict[str, list[dict[str, str]]] = {"data": []}
+    with patch(
+        "superset.common.query_actions._get_full", return_value=expected_payload
+    ) as mock_get_full:
+        assert _get_drill_detail(query_context, query_obj) is expected_payload
+    mock_get_full.assert_called_once()

tests/unit_tests/semantic_layers/models_test.py

@@ -653,6 +653,20 @@ def test_semantic_view_data(
         assert data["table_name"] == "Orders View"
         assert data["datasource_name"] == "Orders View"
         assert data["offset"] == 0
+        # Semantic views don't model raw rows, so neither samples nor
+        # drill-to-detail are available.
+        assert data["supports_samples"] is False
+        assert data["supports_drill_to_detail"] is False
+
+
+def test_semantic_view_supports_samples_is_false() -> None:
+    """The class-level flag opts SemanticView out of the Samples affordance."""
+    assert SemanticView.supports_samples is False
+
+
+def test_semantic_view_supports_drill_to_detail_is_false() -> None:
+    """The class-level flag opts SemanticView out of Drill to detail."""
+    assert SemanticView.supports_drill_to_detail is False
 
 
 def test_semantic_view_get_query_result(

tests/unit_tests/views/datasource/views_test.py

@@ -312,3 +312,66 @@ def test_save_non_owner_with_owners_field_is_rejected(
             raw_save(_view_self())
 
     mock_security_manager.raise_for_ownership.assert_called_once_with(mock_orm)
+
+
+# ---------------------------------------------------------------------------
+# Datasource.samples
+# ---------------------------------------------------------------------------
+
+
+@patch("superset.views.datasource.views._", lambda s: s)
+@patch("superset.views.datasource.views.get_samples")
+@patch("superset.views.datasource.views.json_error_response")
+@patch("superset.views.datasource.views.security_manager", new_callable=MagicMock)
+def test_samples_returns_400_for_unsupported_datasource_type(
+    mock_security_manager: MagicMock,
+    mock_json_error_response: MagicMock,
+    mock_get_samples: MagicMock,
+) -> None:
+    """Semantic views can't return raw samples — endpoint should refuse with 400."""
+    from flask import Flask
+
+    mock_security_manager.is_guest_user.return_value = False
+    mock_json_error_response.return_value = "error-response"
+
+    raw_samples = _get_view_func("samples")
+    app = Flask(__name__)
+    with app.test_request_context(
+        "/datasource/samples?datasource_type=semantic_view&datasource_id=1",
+        method="POST",
+        json={},
+    ):
+        result = raw_samples(_view_self())
+
+    assert result == "error-response"
+    mock_json_error_response.assert_called_once()
+    _, kwargs = mock_json_error_response.call_args
+    assert kwargs.get("status") == 400
+    # The bail-out must happen before any sample fetching is attempted.
+    mock_get_samples.assert_not_called()
+
+
+@patch("superset.views.datasource.views.get_samples")
+@patch("superset.views.datasource.views.security_manager", new_callable=MagicMock)
+def test_samples_proceeds_for_supported_datasource_type(
+    mock_security_manager: MagicMock,
+    mock_get_samples: MagicMock,
+) -> None:
+    """A `query` datasource (supports_samples=True) bypasses the 400 short-circuit."""
+    from flask import Flask
+
+    mock_security_manager.is_guest_user.return_value = False
+    mock_get_samples.return_value = {"rows": []}
+
+    view = _view_self()
+    raw_samples = _get_view_func("samples")
+    app = Flask(__name__)
+    with app.test_request_context(
+        "/datasource/samples?datasource_type=query&datasource_id=1",
+        method="POST",
+        json={},
+    ):
+        raw_samples(view)
+
+    mock_get_samples.assert_called_once()
+    view.json_response.assert_called_once_with({"result": {"rows": []}})