Timeseries to table transformation: Fix misaligned table field values if some frames are missing a label (#78909)

* fix bug with time series table transform when a frame is missing a label

* prettier format

public/app/features/transformers/timeSeriesTable/timeSeriesTableTransformer.test.ts

@@ -216,6 +216,22 @@ describe('timeSeriesTableTransformer', () => {
     expect(results[0].fields[0].values[0].fields[0].values[0]).toBe(10);
     expect(results[0].fields[0].values[0].fields[1].values[0]).toBe(2);
   });
+
+  it('Will correctly fill in gaps in labels', () => {
+    const series = [
+      getTimeSeries('A', { instance: 'A', pod: 'AA' }),
+      getTimeSeries('A', { instance: 'B' }),
+      getTimeSeries('A', { instance: 'C', pod: 'CC' }),
+    ];
+
+    const results = timeSeriesToTableTransform({}, series);
+    expect(results).toHaveLength(1);
+    const result = results[0];
+    expect(result.refId).toBe('A');
+    expect(result.fields).toHaveLength(3);
+    expect(result.fields[0].values).toEqual(['A', 'B', 'C']);
+    expect(result.fields[1].values).toEqual(['AA', '', 'CC']);
+  });
 });
 
 function assertFieldsEqual(field1: Field, field2: Field) {

public/app/features/transformers/timeSeriesTable/timeSeriesTableTransformer.ts

@@ -143,6 +143,30 @@ export function timeSeriesToTableTransform(options: TimeSeriesTableTransformerOp
     // Intialize object for this refId
     refId2trends[refId] = {};
 
+    // Initialize labels object for this refId
+    refId2labelz[refId] = {};
+
+    // Collect all existing label names across frames
+    // so we can fill in nulls for frames that don't
+    // have a particular label
+    const labelNames: string[] = [];
+
+    framesForRef.forEach((frame) => {
+      frame.fields.forEach((field) => {
+        if (field.type !== FieldType.number) {
+          return;
+        }
+        if (field.labels) {
+          Object.keys(field.labels).forEach((labelName) => {
+            if (!labelNames.includes(labelName)) {
+              refId2labelz[refId][labelName] = newField(labelName, FieldType.string);
+              labelNames.push(labelName);
+            }
+          });
+        }
+      });
+    });
+
     for (let i = 0; i < framesForRef.length; i++) {
       const frame = framesForRef[i];
 
@@ -196,19 +220,9 @@ export function timeSeriesToTableTransform(options: TimeSeriesTableTransformerOp
 
         // If there are labels add them to the appropriate fields
         // Because we iterate each frame
-        if (field.labels !== undefined) {
-          for (const [labelKey, labelValue] of Object.entries(field.labels)) {
-            if (refId2labelz[refId] === undefined) {
-              refId2labelz[refId] = {};
-            }
-
-            if (refId2labelz[refId][labelKey] === undefined) {
-              refId2labelz[refId][labelKey] = newField(labelKey, FieldType.string);
-            }
-
-            refId2labelz[refId][labelKey].values.push(labelValue);
-          }
-        }
+        labelNames.forEach((labelName) => {
+          refId2labelz[refId][labelName].values.push(field.labels?.[labelName] ?? '');
+        });
       }
     }
   }