From f66356c8bbeec0260cd56258a27ed08387f42610 Mon Sep 17 00:00:00 2001
From: Krishn <1khandelwalnhk@gmail.com>
Date: Thu, 6 Aug 2026 12:18:11 +0530
Subject: [PATCH] fix(plugin-chart-echarts): hide value labels on zero-height
 stacked segments

thresholdValues[dataIndex] is 0 when percentage_threshold is 0, which is falsy, so the guard fell back to Number.MIN_SAFE_INTEGER and every value passed. A zero-value series occupies no space in a stacked chart, so its label rendered on top of the adjacent segment's label.

Skips the label when the value is exactly 0 while leaving negative values and non-zero thresholds untouched.

Fixes #42702

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 .../src/Timeseries/transformers.ts            |  6 +-
 .../test/Timeseries/transformers.test.ts      | 69 ++++++++++++++++++-
 2 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/superset-frontend/plugins/plugin-chart-echarts/src/Timeseries/transformers.ts b/superset-frontend/plugins/plugin-chart-echarts/src/Timeseries/transformers.ts
index 6d167787d3da..29f135f3de56 100644
--- a/superset-frontend/plugins/plugin-chart-echarts/src/Timeseries/transformers.ts
+++ b/superset-frontend/plugins/plugin-chart-echarts/src/Timeseries/transformers.ts
@@ -467,9 +467,13 @@ export function transformSeries(
           return formatter(numericValue);
         }
         if (!onlyTotal) {
+          // A zero value occupies no space in a stacked series, so its label
+          // would render on top of the adjacent segment's label. Skip it
+          // regardless of the threshold.
           if (
+            numericValue !== 0 &&
             numericValue >=
-            (thresholdValues[dataIndex] || Number.MIN_SAFE_INTEGER)
+              (thresholdValues[dataIndex] || Number.MIN_SAFE_INTEGER)
           ) {
             return formatter(numericValue);
           }
diff --git a/superset-frontend/plugins/plugin-chart-echarts/test/Timeseries/transformers.test.ts b/superset-frontend/plugins/plugin-chart-echarts/test/Timeseries/transformers.test.ts
index 84022759a503..6e043faa2bc4 100644
--- a/superset-frontend/plugins/plugin-chart-echarts/test/Timeseries/transformers.test.ts
+++ b/superset-frontend/plugins/plugin-chart-echarts/test/Timeseries/transformers.test.ts
@@ -26,7 +26,10 @@ import { supersetTheme } from '@apache-superset/core/theme';
 import type { SeriesOption } from 'echarts';
 import type { ScatterSeriesOption } from 'echarts/charts';
 import { EchartsTimeseriesSeriesType } from '../../src';
-import { TIMESERIES_CONSTANTS } from '../../src/constants';
+import {
+  TIMESERIES_CONSTANTS,
+  StackControlsValue,
+} from '../../src/constants';
 import {
   LegendOrientation,
   EchartsTimeseriesChartProps,
@@ -87,6 +90,70 @@ describe('transformSeries', () => {
     );
   });
 
+  describe('stacked value labels', () => {
+    // Two series stacked on one category: A is 32, B is 0. The zero-height
+    // B segment must not render a label over A's label.
+    const buildFormatter = (thresholdValues: number[]) => {
+      const result = transformSeries(series, mockColorScale, 'test-key', {
+        showValue: true,
+        stack: StackControlsValue.Stack,
+        onlyTotal: false,
+        formatter: (v: any) => String(v),
+        totalStackedValues: [32],
+        thresholdValues,
+      });
+      return (result as any).label.formatter;
+    };
+
+    test('hides the label for a zero value when the threshold is 0', () => {
+      const formatter = buildFormatter([0]);
+      expect(
+        formatter({
+          value: [0, 0],
+          dataIndex: 0,
+          seriesIndex: 1,
+          seriesName: 'B',
+        }),
+      ).toBe('');
+    });
+
+    test('still shows the label for a non-zero value when the threshold is 0', () => {
+      const formatter = buildFormatter([0]);
+      expect(
+        formatter({
+          value: [0, 32],
+          dataIndex: 0,
+          seriesIndex: 0,
+          seriesName: 'A',
+        }),
+      ).toBe('32');
+    });
+
+    test('still shows the label for a negative value when the threshold is 0', () => {
+      const formatter = buildFormatter([0]);
+      expect(
+        formatter({
+          value: [0, -5],
+          dataIndex: 0,
+          seriesIndex: 0,
+          seriesName: 'A',
+        }),
+      ).toBe('-5');
+    });
+
+    test('keeps hiding values below a non-zero threshold', () => {
+      const formatter = buildFormatter([16]);
+      expect(
+        formatter({
+          value: [0, 4],
+          dataIndex: 0,
+          seriesIndex: 0,
+          seriesName: 'A',
+        }),
+      ).toBe('');
+    });
+  });
+
   test('should not apply border styles for non-bar series', () => {
     const opts = {
       seriesType: EchartsTimeseriesSeriesType.Line,