Remove workspace_update_8803()

Tagging as a requirement for Drupal 9.0-beta1.

When will the decision be made on what direction to take?

I definitely agree that we should remove this update function in 9.0.x, it makes everything much simpler for most (99% ?) Drupal installs, and the relatively small number of sites that are using core Workspaces can easily update to the latest 8.8.x release before going to 9.0.x.

Regarding the second point form the issue summary, I've read the patch from #3098475-38: Add more strict checking of hook_update_last_removed() and better explanation and, as far as I can tell, it already doesn't allow a site to upgrade if the installed schema version is lower than the value returned by hook_update_last_removed(), so I'm not sure why we'd need a workspace-specific message to that requirements check..

Just discussed this issue with @Berdir and now I see the usefulness of having a workspace-specific message for upgrades from 8.x to 9.x.

We agreed that either this patch or the one from #3098475: Add more strict checking of hook_update_last_removed() and better explanation should be updated, depending on which issue lands first :)

Unrelated PHPunit deprecation test fail.

This will need a reroll - also perhaps we need to wait to see how #3098427-77: Manipulating the revision metadata keys before running the BC layer breaks the BC layer plays out.

I guess I am very reluctantly OK with removing this given the complexities of maintaining it, including #3098427: Manipulating the revision metadata keys before running the BC layer breaks the BC layer and the fact that we've had to fix it like three times already before that. I don't totally love it because beta experimental modules are supposed to have the same upgrade path continuity requirements as stable modules, but mentioning it in the release notes (especially once #3098475: Add more strict checking of hook_update_last_removed() and better explanation is fixed) is probably an OK tradeoff given the complexities of maintaining it.

I think we can have less duplication by doing

    // If system.module is in the list then only show a specific message for
    // Drupal core, otherwise show a more generic message for each module.
    if (isset($module_list['system'])) {
      $requirements['system_update_last_removed'] = [
        'title' => t('The version of Drupal you are trying to update from is too old'),
        'description' => t('Updating to Drupal @current_major is only supported from Drupal version @required_min_version or higher. If you are trying to update from an older version, first update to the latest version of Drupal @previous_major. (<a href=":url">Drupal 9 upgrade guide</a>)', [
          '@current_major' => 9,
          // Workspaces is special cased due to updates being removed after
          // 8.8.0.
          '@required_min_version' => isset($module_list['workspaces']) ? '8.8.2' : '8.8.0',
          '@previous_major' => 8,
          ':url' => 'https://www.drupal.org/docs/9/how-to-prepare-your-drupal-7-or-8-site-for-drupal-9/upgrading-a-drupal-8-site-to-drupal-9',
        ]),
        'severity' => REQUIREMENT_ERROR,
      ];
    }

Less duplicate strings to maintain.

#19 looks great to me!

Post updates are being handled by another issue.

Committed 6cad09c and pushed to 9.0.x. Thanks!

diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 6d3e63988b..317304ba09 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1106,7 +1106,6 @@ function system_requirements($phase) {
       }
     }
 
-
     // If system or workspaces is in the list then only show a specific message
     // for Drupal core.
     if (isset($module_list['system']) || isset($module_list['workspaces'])) {
diff --git a/core/modules/workspaces/workspaces.install b/core/modules/workspaces/workspaces.install
index 047134fd44..75185603c1 100644
--- a/core/modules/workspaces/workspaces.install
+++ b/core/modules/workspaces/workspaces.install
@@ -5,7 +5,6 @@
  * Contains install, update and uninstall functions for the Workspaces module.
  */
 
-use Drupal\Core\Entity\ContentEntityNullStorage;
 use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\workspaces\Entity\Workspace;
 

Fixed coding standards on commit.