Transformations: Match only the field spelled time when Time is configured

When the configured name is Time and the frame has a field named time
(or the other way round), the fallback still matched every time field.
Now it only matches the field with the other spelling, and keeps
matching any time field when no field goes by either name.

packages/grafana-data/src/transformations/matchers/nameMatcher.test.ts

@@ -484,6 +484,14 @@ it('Should only match the field named time when the frame has more time fields',
   expect(namesMatcher(frame.fields[0], frame, [frame])).toBeTruthy();
   expect(namesMatcher(frame.fields[1], frame, [frame])).toBeFalsy();
   expect(namesMatcher(frame.fields[2], frame, [frame])).toBeTruthy();
+
+  const aliasMatcher = getFieldMatcher({
+    id: FieldMatcherID.byName,
+    options: 'Time',
+  });
+  expect(aliasMatcher(frame.fields[0], frame, [frame])).toBeTruthy();
+  expect(aliasMatcher(frame.fields[1], frame, [frame])).toBeFalsy();
+  expect(aliasMatcher(frame.fields[2], frame, [frame])).toBeFalsy();
 });
 
 describe('Fields returned by query with refId', () => {

packages/grafana-data/src/transformations/matchers/nameMatcher.ts

@@ -115,16 +115,20 @@ function fieldNameFallback(fields: Set<string>) {
       );
     };
   } else if (fields.has('Time') || fields.has('time')) {
-    const timeNames = ['Time', 'time'].filter((name) => fields.has(name));
+    const timeNames = ['Time', 'time'];
+    const configuredNames = timeNames.filter((name) => fields.has(name));
     fallback = (field: Field, frame: DataFrame, allFrames: DataFrame[]) => {
-      return (
-        frame.meta?.typeVersion == null &&
-        field.type === FieldType.time &&
-        // A field that already carries the name is matched directly, so other time fields must not be pulled in
-        !frame.fields.some(
-          (f) => timeNames.includes(f.name) || timeNames.includes(getFieldDisplayName(f, frame, allFrames))
-        )
-      );
+      if (frame.meta?.typeVersion != null || field.type !== FieldType.time) {
+        return false;
+      }
+      const hasName = (f: Field, names: string[]) =>
+        names.includes(f.name) || names.includes(getFieldDisplayName(f, frame, allFrames));
+      // A field that already carries the configured name is matched directly, so other time fields must not be pulled in
+      if (frame.fields.some((f) => hasName(f, configuredNames))) {
+        return false;
+      }
+      // Time and time stand in for each other, so only a field with the other spelling is matched when there is one
+      return frame.fields.some((f) => hasName(f, timeNames)) ? hasName(field, timeNames) : true;
     };
   }