Prometheus: Fixes crash in the new options component when range was undefined (#45921)

* Prometheus: Fixes crash in the new options component when range was undefined

* Simplified conditions

public/app/plugins/datasource/prometheus/querybuilder/components/PromQueryBuilderOptions.test.tsx

@@ -59,13 +59,19 @@ describe('PromQueryBuilderOptions', () => {
       legendFormat: '{{label_name}}',
     });
   });
+
+  it('Handle defaults with undefined range', async () => {
+    setup(getQueryWithDefaults({ refId: 'A', expr: '', range: undefined, instant: true }, CoreApp.Dashboard));
+
+    expect(screen.getByText('Type: Instant')).toBeInTheDocument();
+  });
 });
 
 function setup(queryOverrides: Partial<PromQuery> = {}) {
   const props = {
     query: {
       ...getQueryWithDefaults({ refId: 'A' } as PromQuery, CoreApp.PanelEditor),
-      queryOverrides,
+      ...queryOverrides,
     },
     onRunQuery: jest.fn(),
     onChange: jest.fn(),

public/app/plugins/datasource/prometheus/querybuilder/types.ts

@@ -131,14 +131,14 @@ export function getQueryWithDefaults(query: PromQuery, app: CoreApp | undefined)
     result = { ...result, expr: '', legendFormat: LegendFormatMode.Auto };
   }
 
-  // Default to range query
-  if (query.range == null) {
+  if (query.range == null && query.instant == null) {
+    // Default to range query
     result = { ...result, range: true };
-  }
 
-  // In explore we default to both instant & range
-  if (query.instant == null && app === CoreApp.Explore) {
-    result = { ...result, instant: true };
+    // In explore we default to both instant & range
+    if (app === CoreApp.Explore) {
+      result.instant = true;
+    }
   }
 
   return result;