Error: Call to undefined method Drupal\wse\Diff\Form\WseRevisionOverviewForm::getRevisionIds() in Drupal\wse\Diff\Form\WseRevisionOverviewForm->buildForm() (line 28 of modules/contrib/wse/src/Diff/Form/WseRevisionOverviewForm.php)

Hi,

I create a patch for fix.

You need to upgrade the Diff module to a release that contains this issue: ✨ Allow usage of revision comparison inside workspaces Needs review

Thanks.

I test with update Diff module but error persists.

Error: Call to undefined method Drupal\wse\Diff\Form\WseRevisionOverviewForm::getRevisionIds() in Drupal\wse\Diff\Form\WseRevisionOverviewForm->buildForm() (line 28 of modules/contrib/wse/src/Diff/Form/WseRevisionOverviewForm.php).
call_user_func_array() (Line: 528)
Drupal\Core\Form\FormBuilder->retrieveForm() (Line: 279)
Drupal\Core\Form\FormBuilder->buildForm() (Line: 219)
Drupal\Core\Form\FormBuilder->getForm() (Line: 25)
Drupal\wse\Controller\WseDiffNodeRevisionController->revisionOverview()
call_user_func_array() (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 593)
Drupal\Core\Render\Renderer->executeInRenderContext() (Line: 121)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext() (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 183)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 76)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 53)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 28)
Drupal\Core\StackMiddleware\ContentLength->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 36)
Drupal\Core\StackMiddleware\AjaxPageState->handle() (Line: 51)
Drupal\Core\StackMiddleware\StackedHttpKernel->handle() (Line: 709)
Drupal\Core\DrupalKernel->handle() (Line: 19)

You probably need to use the dev → version of the Diff module, because the latest tagged release at this time is 2.0.0-beta3, which doesn't contain the fix linked above.