fix(echarts): fix stacked horizontal bar chart clipping and duplicate x-axis labels (#39012)

(cherry picked from commit 022342839a)

superset-frontend/plugins/plugin-chart-echarts/test/Timeseries/Bar/transformProps.test.ts

@@ -24,6 +24,7 @@ import {
 } from '@superset-ui/core';
 import { GenericDataType } from '@apache-superset/core/common';
 import { supersetTheme } from '@apache-superset/core/theme';
+import { StackControlsValue } from '../../../src/constants';
 import type {
   GridComponentOption,
   LegendComponentOption,
@@ -727,6 +728,97 @@ describe('Bar Chart X-axis Time Formatting', () => {
     });
   });
 
+  describe('Horizontal stacked bar chart axis bounds', () => {
+    // Dataset where each series max = 4 but stacked total max = 8
+    const stackedData: ChartDataResponseResult[] = [
+      createTestQueryData(
+        [
+          { team: 'Team A', High: 2, Low: 2, Medium: 4 },
+          { team: 'Team B', High: null, Low: null, Medium: 3 },
+          { team: 'Team C', High: null, Low: null, Medium: 1 },
+        ],
+        {
+          colnames: ['team', 'High', 'Low', 'Medium'],
+          coltypes: [
+            GenericDataType.String,
+            GenericDataType.Numeric,
+            GenericDataType.Numeric,
+            GenericDataType.Numeric,
+          ],
+        },
+      ),
+    ];
+
+    const horizontalStackedFormData: EchartsTimeseriesFormData = {
+      ...(baseFormData as EchartsTimeseriesFormData),
+      x_axis: 'team',
+      metric: ['High', 'Low', 'Medium'],
+      groupby: [],
+      orientation: OrientationType.Horizontal,
+      seriesType: EchartsTimeseriesSeriesType.Bar,
+      stack: StackControlsValue.Stack,
+      truncateYAxis: true,
+    };
+
+    test('xAxis.max uses stacked total, not individual series max', () => {
+      // Individual series max = 4 (Medium), stacked total for Team A = 8
+      // Without the fix, xAxis.max would be 4, clipping bars and duplicating labels
+      const chartProps = createEchartsTimeseriesTestChartProps<
+        EchartsTimeseriesFormData,
+        EchartsTimeseriesChartProps
+      >({
+        defaultFormData: horizontalStackedFormData,
+        defaultVizType: 'echarts_timeseries_bar',
+        defaultQueriesData: stackedData,
+      });
+
+      const { echartOptions } = transformProps(chartProps);
+      const xAxis = echartOptions.xAxis as any;
+
+      // xAxis.max must be >= stacked total (8), not capped at individual series max (4)
+      expect(xAxis.max).toBeGreaterThanOrEqual(8);
+    });
+
+    test('xAxis.max is not set to individual series max when stacking', () => {
+      const chartProps = createEchartsTimeseriesTestChartProps<
+        EchartsTimeseriesFormData,
+        EchartsTimeseriesChartProps
+      >({
+        defaultFormData: horizontalStackedFormData,
+        defaultVizType: 'echarts_timeseries_bar',
+        defaultQueriesData: stackedData,
+      });
+
+      const { echartOptions } = transformProps(chartProps);
+      const xAxis = echartOptions.xAxis as any;
+
+      // 4 is the individual series max — the axis should not be clipped there
+      expect(xAxis.max).not.toBe(4);
+    });
+
+    test('non-stacked horizontal bar chart still uses individual series max', () => {
+      const nonStackedFormData: EchartsTimeseriesFormData = {
+        ...horizontalStackedFormData,
+        stack: null,
+      };
+
+      const chartProps = createEchartsTimeseriesTestChartProps<
+        EchartsTimeseriesFormData,
+        EchartsTimeseriesChartProps
+      >({
+        defaultFormData: nonStackedFormData,
+        defaultVizType: 'echarts_timeseries_bar',
+        defaultQueriesData: stackedData,
+      });
+
+      const { echartOptions } = transformProps(chartProps);
+      const xAxis = echartOptions.xAxis as any;
+
+      // Without stacking, xAxis.max should be based on individual series values
+      expect(xAxis.max).toBe(4);
+    });
+  });
+
   describe('Legend layout regressions', () => {
     const getBottomLegendLayout = (
       chartWidth: number,