Pyroscope: Fix error when no profile types are returned (#75143)

public/app/plugins/datasource/grafana-pyroscope-datasource/QueryEditor/ProfileTypesCascader.tsx

@@ -9,6 +9,7 @@ type Props = {
   initialProfileTypeId?: string;
   profileTypes?: ProfileTypeMessage[];
   onChange: (value: string) => void;
+  placeholder?: string;
 };
 
 export function ProfileTypesCascader(props: Props) {
@@ -16,6 +17,7 @@ export function ProfileTypesCascader(props: Props) {
 
   return (
     <Cascader
+      placeholder={props.placeholder}
       separator={'-'}
       displayAllSelectedLevels={true}
       initialValue={props.initialProfileTypeId}

public/app/plugins/datasource/grafana-pyroscope-datasource/QueryEditor/QueryEditor.test.tsx

@@ -16,6 +16,26 @@ describe('QueryEditor', () => {
     expect(await screen.findByDisplayValue('process_cpu-cpu')).toBeDefined();
   });
 
+  it('should render without error if empty profileTypes', async () => {
+    const ds = setupDs();
+    ds.getProfileTypes = jest.fn().mockResolvedValue([]);
+    setup({
+      props: {
+        datasource: ds,
+        query: {
+          queryType: 'both',
+          labelSelector: '',
+          profileTypeId: '',
+          refId: 'A',
+          maxNodes: 1000,
+          groupBy: [],
+        },
+      },
+    });
+
+    expect(await screen.findByPlaceholderText('No profile types found')).toBeDefined();
+  });
+
   it('should render options', async () => {
     setup();
     await openOptions();
@@ -41,8 +61,7 @@ async function openOptions() {
   await userEvent.click(options);
 }
 
-function setup(options: { props: Partial<Props> } = { props: {} }) {
-  const onChange = jest.fn();
+function setupDs() {
   const ds = new PhlareDataSource({
     name: 'test',
     uid: 'test',
@@ -85,6 +104,11 @@ function setup(options: { props: Partial<Props> } = { props: {} }) {
     },
   ] as ProfileTypeMessage[]);
 
+  return ds;
+}
+
+function setup(options: { props: Partial<Props> } = { props: {} }) {
+  const onChange = jest.fn();
   const utils = render(
     <QueryEditor
       query={{
@@ -95,7 +119,7 @@ function setup(options: { props: Partial<Props> } = { props: {} }) {
         maxNodes: 1000,
         groupBy: [],
       }}
-      datasource={ds}
+      datasource={setupDs()}
       onChange={onChange}
       onRunQuery={() => {}}
       app={CoreApp.Explore}

public/app/plugins/datasource/grafana-pyroscope-datasource/QueryEditor/QueryEditor.tsx

@@ -28,25 +28,28 @@ export function QueryEditor(props: Props) {
   const { labels, getLabelValues, onLabelSelectorChange } = useLabels(range, datasource, query, onChange);
   useNormalizeQuery(query, profileTypes, onChange, app);
 
+  let cascader = <LoadingPlaceholder text={'Loading'} />;
+
+  // The cascader is uncontrolled component so if we want to set some default value we can do it only on initial
+  // render, so we are waiting until we have the profileTypes and know what the default value should be before
+  // rendering.
+  if (profileTypes && query.profileTypeId !== undefined) {
+    cascader = (
+      <ProfileTypesCascader
+        placeholder={profileTypes.length === 0 ? 'No profile types found' : 'Select profile type'}
+        profileTypes={profileTypes}
+        initialProfileTypeId={query.profileTypeId}
+        onChange={(val) => {
+          onChange({ ...query, profileTypeId: val });
+        }}
+      />
+    );
+  }
+
   return (
     <EditorRows>
       <EditorRow stackProps={{ wrap: false, gap: 1 }}>
-        {/*
-            The cascader is uncontrolled component so if we want to set some default value we can do it only on initial
-            render, so we are waiting until we have the profileTypes and know what the default value should be before
-            rendering.
-         */}
-        {profileTypes && query.profileTypeId ? (
-          <ProfileTypesCascader
-            profileTypes={profileTypes}
-            initialProfileTypeId={query.profileTypeId}
-            onChange={(val) => {
-              onChange({ ...query, profileTypeId: val });
-            }}
-          />
-        ) : (
-          <LoadingPlaceholder text={'Loading'} />
-        )}
+        {cascader}
         <LabelsEditor
           value={query.labelSelector}
           onChange={onLabelSelectorChange}
@@ -98,7 +101,7 @@ function defaultProfileType(profileTypes: ProfileTypeMessage[]): string {
   }
 
   // Fallback to first profile type from response data
-  return profileTypes[0].id;
+  return profileTypes[0]?.id || '';
 }
 
 function useLabels(