TimeseriesPanel: Preserve string fields for data link interpolation (#58424)

* TimeseriesPanel: Preserve string fields for data link interpolation

* clean code

* Modify tests so that string fields are allowed only when a valid time/number dataframe exists

* performance mods

* fix wrong length

* remove console.log

* Check if aligned dataframe has links

packages/grafana-data/src/vector/SortedVector.ts

@@ -23,4 +23,8 @@ export class SortedVector<T = any> implements Vector<T> {
   toJSON(): T[] {
     return vectorToArray(this);
   }
+
+  getOrderArray(): number[] {
+    return this.order;
+  }
 }

public/app/plugins/panel/timeseries/TimeSeriesPanel.tsx

@@ -1,6 +1,6 @@
 import React, { useMemo } from 'react';
 
-import { Field, PanelProps, getLinksSupplier } from '@grafana/data';
+import { Field, PanelProps } from '@grafana/data';
 import { PanelDataErrorView } from '@grafana/runtime';
 import { TooltipDisplayMode } from '@grafana/schema';
 import { usePanelContext, TimeSeries, TooltipPlugin, ZoomPlugin, KeyboardPlugin } from '@grafana/ui';
@@ -14,7 +14,7 @@ import { ExemplarsPlugin } from './plugins/ExemplarsPlugin';
 import { OutsideRangePlugin } from './plugins/OutsideRangePlugin';
 import { ThresholdControlsPlugin } from './plugins/ThresholdControlsPlugin';
 import { TimeSeriesOptions } from './types';
-import { getTimezones, prepareGraphableFields } from './utils';
+import { getTimezones, prepareGraphableFields, regenerateLinksSupplier } from './utils';
 
 interface TimeSeriesPanelProps extends PanelProps<TimeSeriesOptions> {}
 
@@ -65,15 +65,11 @@ export const TimeSeriesPanel: React.FC<TimeSeriesPanelProps> = ({
       options={options}
     >
       {(config, alignedDataFrame) => {
-        alignedDataFrame.fields.forEach((field) => {
-          field.getLinks = getLinksSupplier(
-            alignedDataFrame,
-            field,
-            field.state!.scopedVars!,
-            replaceVariables,
-            timeZone
-          );
-        });
+        if (
+          alignedDataFrame.fields.filter((f) => f.config.links !== undefined && f.config.links.length > 0).length > 0
+        ) {
+          alignedDataFrame = regenerateLinksSupplier(alignedDataFrame, frames, replaceVariables, timeZone);
+        }
 
         return (
           <>

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

@@ -43,7 +43,7 @@ describe('prepare timeseries graph', () => {
     const frames = prepareGraphableFields(input, createTheme());
     const out = frames![0];
 
-    expect(out.fields.map((f) => f.name)).toEqual(['a', 'c', 'd']);
+    expect(out.fields.map((f) => f.name)).toEqual(['a', 'b', 'c', 'd']);
 
     const field = out.fields.find((f) => f.name === 'c');
     expect(field?.display).toBeDefined();

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

@@ -4,8 +4,11 @@ import {
   Field,
   FieldType,
   getDisplayProcessor,
+  getLinksSupplier,
   GrafanaTheme2,
+  InterpolateFunction,
   isBooleanUnit,
+  SortedVector,
   TimeRange,
 } from '@grafana/data';
 import { GraphFieldConfig, LineInterpolation } from '@grafana/schema';
@@ -60,6 +63,14 @@ export function prepareGraphableFields(
             ),
           };
 
+          fields.push(copy);
+          break; // ok
+        case FieldType.string:
+          copy = {
+            ...field,
+            values: new ArrayVector(field.values.toArray()),
+          };
+
           fields.push(copy);
           break; // ok
         case FieldType.boolean:
@@ -123,3 +134,46 @@ export function getTimezones(timezones: string[] | undefined, defaultTimezone: s
   }
   return timezones.map((v) => (v?.length ? v : defaultTimezone));
 }
+
+export function regenerateLinksSupplier(
+  alignedDataFrame: DataFrame,
+  frames: DataFrame[],
+  replaceVariables: InterpolateFunction,
+  timeZone: string
+): DataFrame {
+  alignedDataFrame.fields.forEach((field) => {
+    const frameIndex = field.state?.origin?.frameIndex;
+
+    if (frameIndex === undefined) {
+      return;
+    }
+
+    const frame = frames[frameIndex];
+    const tempFields: Field[] = [];
+
+    /* check if field has sortedVector values
+      if it does, sort all string fields in the original frame by the order array already used for the field
+      otherwise just attach the fields to the temporary frame used to get the links
+    */
+    for (const frameField of frame.fields) {
+      if (frameField.type === FieldType.string) {
+        if (field.values instanceof SortedVector) {
+          const copiedField = { ...frameField };
+          copiedField.values = new SortedVector(frameField.values, field.values.getOrderArray());
+          tempFields.push(copiedField);
+        } else {
+          tempFields.push(frameField);
+        }
+      }
+    }
+
+    const tempFrame: DataFrame = {
+      fields: [...alignedDataFrame.fields, ...tempFields],
+      length: alignedDataFrame.fields.length + tempFields.length,
+    };
+
+    field.getLinks = getLinksSupplier(tempFrame, field, field.state!.scopedVars!, replaceVariables, timeZone);
+  });
+
+  return alignedDataFrame;
+}