Cannot reinstall module after uninstall

Maybe adding:

dependencies:
  module:
    - robotstxt

helps.

See http://cgit.drupalcode.org/robotstxt/tree/config/install/migrate.migrati... is missing that.

Waiting on suggestion from dawhner

I believe core is supposed to automatically delete configuration when a module is uninstalled, but it doesn't seem to be happening (I see the issue with migrate_drupal, as well as my own migrate_plus sandbox).

It appears that only configuration entities keyed by the module itself are deleted, not entities the module instantiates from entity types defined by another module. E.g., if robotstxt defined its own configuration entity type "robot" and had a robotstxt.robot.default.yml file in schema/install, robotstxt.robot.default would be deleted, but as seen above migrate.migration.d6_robotstxt_settings is not. I'm looking now at ConfigManager::findConfigEntityDependentsAsEntities().

As far as I can tell, this is a general issue that any module which installs configuration entities based on another module's config entity type cannot be reinstalled after being installed. Looks critical to me.

For reference, my IRC chat with @chx:

chx: mikeryan1: if i needed to make a guess
[3:16pm] chx: mikeryan1: it only deletes the config where the first part is the module being uninstalled
[3:16pm] chx: mikeryan1: so ... if your module installs a view, it's very hard to figure out your module did it
[3:16pm] mikeryan1: I got far enough to see that in ConfigManager::uninstall(), getConfigEntitiesToChangeOnDependencyRemoval() isn’t returning anything to delete
[3:17pm] mikeryan1: First part of the config key?
[3:19pm] chx: this is interesting
[3:19pm] chx: ah
[3:20pm] chx: foreach ($this->activeStorage->getAllCollectionNames() as $collection) {
[3:20pm] chx: $collection_storage = $this->activeStorage->createCollection($collection);
[3:20pm] chx: $collection_storage->deleteAll($name . '.');
[3:20pm] chx: mikeryan1: ^ this is what i meant
[3:20pm] chx: mikeryan1: if you uninstall module foo then it uninstalls foo.*
[3:20pm] chx: mikeryan1: but i am wrong -- apparetly it tries to remove entities as well. that part i do not understand.
[3:22pm] mikeryan1: Fails in UI too
[3:24pm] mikeryan1: I think we’re looking at a critical here
[3:28pm] mikeryan1: Right, before it gets to that point it’s trying to delete dependent config entities, but getConfigEntitiesToChangeOnDependencyRemoval() isn’t returning any
[3:28pm]

OK, @xjm has helped clarify things - @dawehner had the right idea above, I wasn't aware that one needed to declare a dependency on your own module for configuration to be deleted on uninstall. It's up to robotstxt to fix this.

This has been illuminating - migrate_drupal in core needs to also deal with this.

The migrations are defined in config/install, thus are installed when the module is installed. The idea of the dependency is that when the module is uninstalled, any configuration entities with a dependency on the module will be removed.

The problem with http://cgit.drupalcode.org/google_analytics/commit/?id=88b5c55 is it needs to use an enforced dependency instead.

Relevant change record: https://www.drupal.org/node/2404447

@hass, I tried it and it seems to work fine? You might want to start fresh with your D8 parent site to get rid of the stale config, or try uninstalling migrate to clean up the stale config, which also should delete it without the need for a dependency key.

Filed: #2460529: Migrations need to use the configuration entity dependency system

This is a bug in the Migration module - considering it choose to use config entities to store migrations in ConfigEntities then is has to use the Config entity dependency system properly. If a migration is for migration a piece of configuration for a module then it should have a dependency on that module. Basically we need to implement a calculateDependencies method. Or make migrations not configuration entities.

Wrt to the Robot.txt module it should move the migration into config/optional because it is should only be created when the migrate module is installed - that will the fix the install and reinstall error.

@hass: There are already core issues around the general problem with migrate configuration entities (#2460301: Migration config entities don't store dependencies, #2460301: Migration config entities don't store dependencies, #2459619: migrate_drupal cannot be uninstalled and reinstalled - this issue here is about what the RobotsTxt module needs to do once those issues are addressed.

@hass yep just move your migration config entity to config/optional - adding dependencies to it won't really work until #2460301: Migration config entities don't store dependencies is addressed