I have just upgraded a site from Drupal 8.7 to 8.8, and I now have a broken site.
Pages on the site (mainly admin pages) are now giving the following error:
Drupal\Component\Plugin\Exception\PluginNotFoundException: The "entity:path_alias" plugin does not exist. Valid plugin IDs for Drupal\Core\TypedData\TypedDataManager are: entity_revision, entity_revision:block, entity_revision:block_content, entity_revision:block_content:basic, entity_revision:block_content:paragraph_in_block_display, entity_revision:block_content_type ...
(I've truncated it because it goes on at some length about the entity types available)
Clearly something has gone wrong during the upgrade process. I've run all the module updates via composer, and database upgrades, and imported the config that was exported from a development instance of the site that has successfully been upgraded.
drush updbtells me that all the database updates have been done.
drush cimtells me that my config has been imported correctly.
drush en pathauto, path_aliastells me that those modules are already installed.
drush crclears the cache, but does not resolve the issue.
I'm aware that the issue is due to the Pathauto / path_alias changes that occurred between D8.7 and D8.8, and I'm aware that I've probably missed a step during the upgrade process. That doesn't matter right now; what matters is how to fix it now that I'm in this situation. Any help appreciated.