Remove default color assignment for lineStyle

 - remove color assignment
 - remove related test
 - remove constant definition

app/assets/javascripts/monitoring/components/charts/time_series.vue

@@ -13,7 +13,6 @@ import {
   lineWidths,
   symbolSizes,
   dateFormats,
-  chartColorValues,
 } from '../../constants';
 import { getYAxisOptions, getChartGrid, getTooltipFormatter } from './options';
 import { makeDataSeries } from '~/helpers/monitor_helper';
@@ -124,7 +123,7 @@ export default {
       // Transforms & supplements query data to render appropriate labels & styles
       // Input: [{ queryAttributes1 }, { queryAttributes2 }]
       // Output: [{ seriesAttributes1 }, { seriesAttributes2 }]
-      return this.graphData.metrics.reduce((acc, query, i) => {
+      return this.graphData.metrics.reduce((acc, query) => {
         const { appearance } = query;
         const lineType =
           appearance && appearance.line && appearance.line.type
@@ -145,7 +144,6 @@ export default {
           lineStyle: {
             type: lineType,
             width: lineWidth,
-            color: chartColorValues[i % chartColorValues.length],
           },
           showSymbol: false,
           areaStyle: this.graphData.type === 'area-chart' ? areaStyle : undefined,

app/assets/javascripts/monitoring/constants.js

@@ -68,13 +68,6 @@ export const colorValues = {
   anomalyAreaColor: '#1f78d1',
 };
 
-export const chartColorValues = [
-  '#1f78d1', // $blue-500 (see variables.scss)
-  '#1aaa55', // $green-500
-  '#fc9403', // $orange-500
-  '#6d49cb', // $purple
-];
-
 export const lineTypes = {
   default: 'solid',
 };

changelogs/unreleased/202620-charts-with-series-that-contain-multiple-labels-do-not-have-unique.yml

+---
+title: Fix wrong colors displayed in charts
+merge_request: 28095
+author:
+type: fixed

spec/frontend/monitoring/components/charts/time_series_spec.js

@@ -4,7 +4,6 @@ import { GlLink } from '@gitlab/ui';
 import { GlAreaChart, GlLineChart, GlChartSeriesLabel } from '@gitlab/ui/dist/charts';
 import { cloneDeep } from 'lodash';
 import { shallowWrapperContainsSlotText } from 'helpers/vue_test_utils_helper';
-import { chartColorValues } from '~/monitoring/constants';
 import { createStore } from '~/monitoring/stores';
 import TimeSeries from '~/monitoring/components/charts/time_series.vue';
 import * as types from '~/monitoring/stores/mutation_types';
@@ -308,10 +307,6 @@ describe('Time series component', () => {
           it('formats line width correctly', () => {
             expect(chartData[0].lineStyle.width).toBe(2);
           });
-
-          it('formats line color correctly', () => {
-            expect(chartData[0].lineStyle.color).toBe(chartColorValues[0]);
-          });
         });
 
         describe('chartOptions', () => {