TimeSeries: Preserve RegExp series overrides when transforming from old graph (#36134)

public/app/plugins/panel/timeseries/__snapshots__/migrations.test.ts.snap

@@ -155,6 +155,60 @@ Object {
 }
 `;
 
+exports[`Graph Migrations preserves series overrides using a regex alias 1`] = `
+Object {
+  "fieldConfig": Object {
+    "defaults": Object {
+      "custom": Object {
+        "axisPlacement": "hidden",
+        "drawStyle": "line",
+        "fillOpacity": 60,
+        "gradientMode": "opacity",
+        "lineInterpolation": "stepAfter",
+        "lineWidth": 1,
+        "showPoints": "never",
+        "spanNulls": true,
+      },
+      "nullValueMode": "null",
+      "unit": "short",
+    },
+    "overrides": Array [
+      Object {
+        "matcher": Object {
+          "id": "byRegexp",
+          "options": "/^A-/",
+        },
+        "properties": Array [
+          Object {
+            "id": "color",
+            "value": Object {
+              "fixedColor": "rgba(165, 72, 170, 0.77)",
+              "mode": "fixed",
+            },
+          },
+        ],
+      },
+    ],
+  },
+  "options": Object {
+    "legend": Object {
+      "calcs": Array [
+        "mean",
+        "lastNotNull",
+        "max",
+        "min",
+        "sum",
+      ],
+      "displayMode": "table",
+      "placement": "bottom",
+    },
+    "tooltip": Object {
+      "mode": "single",
+    },
+  },
+}
+`;
+
 exports[`Graph Migrations simple bars 1`] = `
 Object {
   "fieldConfig": Object {

public/app/plugins/panel/timeseries/migrations.test.ts

@@ -1,5 +1,6 @@
 import { PanelModel, FieldConfigSource } from '@grafana/data';
 import { graphPanelChangedHandler } from './migrations';
+import { cloneDeep } from 'lodash';
 
 describe('Graph Migrations', () => {
   let prevFieldConfig: FieldConfigSource;
@@ -67,6 +68,15 @@ describe('Graph Migrations', () => {
     expect(panel).toMatchSnapshot();
   });
 
+  it('preserves series overrides using a regex alias', () => {
+    const old: any = {
+      angular: customColorRegex,
+    };
+    const panel = {} as PanelModel;
+    panel.options = graphPanelChangedHandler(panel, 'graph', old, prevFieldConfig);
+    expect(panel).toMatchSnapshot();
+  });
+
   describe('legend', () => {
     test('without values', () => {
       const old: any = {
@@ -383,6 +393,9 @@ const customColor = {
   datasource: null,
 };
 
+const customColorRegex = cloneDeep(customColor);
+customColorRegex.seriesOverrides[0].alias = '/^A-/';
+
 const stairscase = {
   aliasColors: {},
   dashLength: 10,

public/app/plugins/panel/timeseries/migrations.ts

@@ -112,9 +112,10 @@ export function flotToGraphOptions(angular: any): { fieldConfig: FieldConfigSour
       if (!seriesOverride.alias) {
         continue; // the matcher config
       }
+      const aliasIsRegex = seriesOverride.alias.startsWith('/') && seriesOverride.alias.endsWith('/');
       const rule: ConfigOverrideRule = {
         matcher: {
-          id: FieldMatcherID.byName,
+          id: aliasIsRegex ? FieldMatcherID.byRegexp : FieldMatcherID.byName,
           options: seriesOverride.alias,
         },
         properties: [],