Thanks for the very promising module. If I can ever get it to work, I'm sure it will be a lifesaver.
I'm using Drupal 8.8.2. I installed the Feeds Migrate module using composer (composer require 'drupal/feeds_migrate:1.x-dev'). When I enabled the module it rendered my site unusable and returned the following error. Uninstalling the Feeds Migrate module returns my site to usable:
The website encountered an unexpected error. Please try again later.
Symfony\Component\Routing\Exception\RouteNotFoundException: Route "entity.migration.add_form" does not exist. in Drupal\Core\Routing\RouteProvider->getRouteByName() (line 208 of core\lib\Drupal\Core\Routing\RouteProvider.php).
Drupal\Core\Routing\UrlGenerator->getRoute('entity.migration.add_form') (Line: 130)
Drupal\Core\Routing\UrlGenerator->getPathFromRoute('entity.migration.add_form', Array) (Line: 68)
Drupal\Core\Render\MetadataBubblingUrlGenerator->getPathFromRoute('entity.migration.add_form', Array) (Line: 791)
Drupal\Core\Url->getInternalPath() (Line: 135)
Drupal\Core\Utility\LinkGenerator->generate('Add Migration', Object) (Line: 95)
Drupal\Core\Render\Element\Link::preRenderLink(Array)
call_user_func_array(Array, Array) (Line: 100)
Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. Support for this callback implementation is deprecated in 8.8.0 and will be removed in Drupal 9.0.0. See https://www.drupal.org/node/2966725', 'silenced_deprecation', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 781)
Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 372)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 501)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 117)
__TwigTemplate_1fb845d8f4ff14ee04082993964316ffb64d7366a29061830fb010db7e98fcbf->getmenu_links(Array, Object, 1) (Line: 124)
__TwigTemplate_1fb845d8f4ff14ee04082993964316ffb64d7366a29061830fb010db7e98fcbf->getmenu_links(Array, Object, 0) (Line: 60)
__TwigTemplate_1fb845d8f4ff14ee04082993964316ffb64d7366a29061830fb010db7e98fcbf->doDisplay(Array, Array) (Line: 455)
Twig\Template->displayWithErrorHandling(Array, Array) (Line: 422)
Twig\Template->display(Array) (Line: 434)
Twig\Template->render(Array) (Line: 64)
twig_render_template('core/themes/stable/templates/navigation/menu--toolbar.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('menu__toolbar', Array) (Line: 431)
Drupal\Core\Render\Renderer->doRender(Array, 1) (Line: 200)
Drupal\Core\Render\Renderer->render(Array, 1) (Line: 156)
Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 157)
Drupal\Core\Render\Renderer->renderPlain(Array) (Line: 115)
Drupal\toolbar\Controller\ToolbarController::preRenderGetRenderedSubtrees(Array)
call_user_func_array(Array, Array) (Line: 100)
Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. Support for this callback implementation is deprecated in 8.8.0 and will be removed in Drupal 9.0.0. See https://www.drupal.org/node/2966725', 'silenced_deprecation', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 781)
Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 372)
Drupal\Core\Render\Renderer->doRender(Array, 1) (Line: 200)
Drupal\Core\Render\Renderer->render(Array, 1) (Line: 156)
Drupal\Core\Render\Renderer->Drupal\Core\Render\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 157)
Drupal\Core\Render\Renderer->renderPlain(Array) (Line: 299)
toolbar_get_rendered_subtrees() (Line: 324)
_toolbar_get_subtrees_hash() (Line: 167)
toolbar_toolbar()
call_user_func_array('toolbar_toolbar', Array) (Line: 403)
Drupal\Core\Extension\ModuleHandler->invokeAll('toolbar') (Line: 81)
Drupal\toolbar\Element\Toolbar::preRenderToolbar(Array)
call_user_func_array(Array, Array) (Line: 100)
Drupal\Core\Render\Renderer->doTrustedCallback(Array, Array, 'Render #pre_render callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. The callback was %s. Support for this callback implementation is deprecated in 8.8.0 and will be removed in Drupal 9.0.0. See https://www.drupal.org/node/2966725', 'silenced_deprecation', 'Drupal\Core\Render\Element\RenderCallbackInterface') (Line: 781)
Drupal\Core\Render\Renderer->doCallback('#pre_render', Array, Array) (Line: 372)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 444)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 501)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 98)
__TwigTemplate_abdcdd41d2b3f20a982a05a7fe85fd8ae0e26decee18497d05ed1983cbad61f0->doDisplay(Array, Array) (Line: 455)
Twig\Template->displayWithErrorHandling(Array, Array) (Line: 422)
Twig\Template->display(Array) (Line: 434)
Twig\Template->render(Array) (Line: 64)
twig_render_template('core/themes/classy/templates/layout/html.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('html', Array) (Line: 431)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 200)
Drupal\Core\Render\Renderer->render(Array) (Line: 147)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 148)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
call_user_func(Array, Object, 'kernel.view', Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object) (Line: 156)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 106)
Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 85)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 694)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)