[regression] \Drupal\user\ContextProvider\CurrentUserContext broken for anonymous users

I changed category from Bug report to Support request after I tested on simplytest.me and couldn't reproduce the error. So it seems it's something with my install but I have yet to figure it out hopefully with your kind help here.

If someone can direct me in the right direction for how to debug it and find the culprit, it would be greatly appreciated.

Thank you

I should've added that I first ran the update from D 8.5.5 with composer update and that updated to D 8.5.7 instead of 8.6.0

Trying to make it update to the latest 8.6.0, I tried several composer commands to no avail until I edited the composer.json and changed drupal core versions to ^8.6.0 and then:
composer update drupal/core webflo/* --with-dependencies

That made the update from 8.5.7 to 8.6.0 succeed.

I then: drush updatedb

Then: drush cr

I tested as admin user and all looked fine except for the breadcrumbs menu first showing the word "node" instead of the title of the node !! This seemed to solve itself later idk how or if related to drush cr I did .

I tested as anonymous and that's when I first noticed the TypeError.

The only common trigger among troublesome blocks seems to be setting block visibility by Roles whether alone or in addition to others. Other visibility settings don't seem to trigger the error.

The type of block doesn't seem to matter. I even tried setting the visibility by roles for the "Site Branding" block and that triggered the error.

I have the Content Access module installed if that may matter to know.

I don't know what else to try. Please advise me on what else I could do.

I was going to move the site to production right before I made this bad update!

+ In addition to the oroginal error mentioned here, I have the below warning (which is reported by others elsewhere lately) when I browse to /admin/reports/dblog

Warning: Illegal string offset 'value' in Drupal\views\Plugin\views\area\Text->preQuery() (line 50 of core\modules\views\src\Plugin\views\area\Text.php).

		Drupal\views\Plugin\views\area\Text->preQuery() (Line: 1011)
		Drupal\views\ViewExecutable->_preQuery() (Line: 1233)
		Drupal\views\ViewExecutable->build() (Line: 390)
		Drupal\views\Plugin\views\display\PathPluginBase->execute() (Line: 180)
		Drupal\views\Plugin\views\display\Page->execute() (Line: 1630)
		Drupal\views\ViewExecutable->executeDisplay('page', Array) (Line: 77)
		Drupal\views\Element\View::preRenderViewElement(Array)
		call_user_func(Array, Array) (Line: 378)
		Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
		Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
		Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 582)
		Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
		Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
		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: 99)
		Drupal\page_cache\StackMiddleware\PageCache->pass(Object, 1, 1) (Line: 78)
		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: 665)
		Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

Thanks

I'm wondering if this issue is somehow related to Block visibility setting tab for Roles not showing (2952962)

A list of installed modules just in case:

drush config-get core.extension module

'core.extension:module':
  addtoany: 0
  automated_cron: 0
  big_pipe: 0
  block: 0
  block_content: 0
  book: 0
  breakpoint: 0
  checklistapi: 0
  ckeditor: 0
  ckeditor_media_embed: 0
  color: 0
  comment: 0
  config: 0
  config_translation: 0
  contact: 0
  content_access: 0
  contextual: 0
  datetime: 0
  datetime_range: 0
  dblog: 0
  draggableviews: 0
  editor: 0
  editor_advanced_link: 0
  fakeobjects: 0
  field: 0
  field_ui: 0
  file: 0
  filter: 0
  footnotes: 0
  help: 0
  hierarchical_taxonomy_menu: 0
  history: 0
  image: 0
  imce: 0
  language: 0
  link: 0
  linkit: 0
  locale: 0
  menu_ui: 0
  migrate: 0
  migrate_drupal: 0
  migrate_drupal_multilingual: 0
  migrate_drupal_ui: 0
  migrate_manifest: 0
  migrate_plus: 0
  migrate_tools: 0
  migrate_upgrade: 0
  node: 0
  options: 0
  path: 0
  quickedit: 0
  responsive_image: 0
  search: 0
  seo_checklist: 0
  shortcut: 0
  social_media_links: 0
  statistics: 0
  system: 0
  taxonomy: 0
  telephone: 0
  text: 0
  toolbar: 0
  tour: 0
  tracker: 0
  update: 0
  user: 0
  views_ui: 0
  weight: 0
  menu_link_content: 1
  content_translation: 10
  views: 10
  standard: 1000

Any help whatsoever !!! Any hints on where/how to start to troubleshoot this issue/bug ???

Unfortunately, I was so lazy to make a backup before that stupid update and my only option now to use a module to set different theme for different roles and remove any visibility restrictions by Roles from any block in the theme for anonymous.

This still does NOT address the original issue/bug but my experience with drupal support over more than 10 years has been very very negative and in most cases I ended up solving things on my own unlike this time I feel I'm out of ideas or directions where to go next.

This is a minor version (feature release) of Drupal 8 and is ready for use on production sites

The above statement on the drupal 8.6.0 release page is misleading and I think shouldn't be there. A BIG warning and reminder to backup and be ready for the worst should be in its place instead.

It seems drupal is trying hard to push its loyal users away. Everything is changing all the time and one just needs to keep running to catch up ! That's including in addition to drupal major upgrades and the big changes involved, changes in drush versions and deprecation of some helpful commands, as well as the still not user-friendly nor intuitive at all composer and yet, drupal is somehow forcing everyone to use drush and composer !!!

Thanks for your understanding and if not then please spare me any lectures. That's how I feel and I'm sure so many others do whether some like it or not.

If anyone is reading ever !

@mwnemesis thanks so much for sharing the fix, it worked for me too.

It would be great though if you share more info on the steps you took to do the update and how you could reproduce the issue and if any different than my steps, did you update via composer/drush or UI ? what modules do you have installed ? any other info to help shed more light on the culprit and hopefully get drupal developers more interested in fixing this bug/issue at its root .

In the meantime, I had found a way around so I could allow anonymous users to browse the site and same time hide restricted blocks from them. I did so by using the role_theme_switcher module and enabling a different theme (actually a copy of my original theme) and removing the blocks that are not meant for anonymous users from it in its settings. I am probably going to keep this later on, even if the root cause of this issue was found and fixed, because it gives me more peace of mind and more control over what to show to each role.