public dashboards:fix time regression (#51998)

This PR fixes a regression bug for public dashboards and adds a test to ensure the regression does not resurface.

public/app/features/dashboard/components/ShareModal/SharePublicDashboard.test.tsx

@@ -96,10 +96,28 @@ describe('SharePublic', () => {
     await screen.findByText('Welcome to Grafana public dashboards alpha!');
   });
 
-  // test when checkboxes show up
+  it('renders default time in inputs', async () => {
-  // test checkboxes hidden
+    config.featureToggles.publicDashboards = true;
-  // test url hidden
+    const mockDashboard = new DashboardModel({
-  // test url shows up
+      uid: 'mockDashboardUid',
-  //
+    });
+    const mockPanel = new PanelModel({
+      id: 'mockPanelId',
+    });
+
+    expect(mockDashboard.time).toEqual({ from: 'now-6h', to: 'now' });
+    //@ts-ignore
+    mockDashboard.originalTime = { from: 'test-from', to: 'test-to' };
+
+    render(<ShareModal panel={mockPanel} dashboard={mockDashboard} onDismiss={() => {}} />);
+
+    await waitFor(() => screen.getByText('Link'));
+    fireEvent.click(screen.getByText('Public Dashboard'));
+
+    await screen.findByText('Welcome to Grafana public dashboards alpha!');
+    expect(screen.getByDisplayValue('test-from')).toBeInTheDocument();
+    expect(screen.getByDisplayValue('test-to')).toBeInTheDocument();
+  });
+
   // test checking if current version of dashboard in state is persisted to db
 });

public/app/features/dashboard/components/ShareModal/SharePublicDashboard.tsx

@@ -164,14 +164,14 @@ export const SharePublicDashboard = (props: Props) => {
               <br />
               <div style={{ padding: '5px' }}>
                 <Input
-                  value={props.dashboard.time.from}
+                  value={props.dashboard.getDefaultTime().from}
                   disabled={true}
                   addonBefore={
                     <span style={{ width: '50px', display: 'flex', alignItems: 'center', padding: '5px' }}>From:</span>
                   }
                 />
                 <Input
-                  value={props.dashboard.time.to}
+                  value={props.dashboard.getDefaultTime().to}
                   disabled={true}
                   addonBefore={
                     <span style={{ width: '50px', display: 'flex', alignItems: 'center', padding: '5px' }}>To:</span>