Single item import fails with validation errors from other config

The migration from Drupal 7 to 10 is just a really bad mess. Nothing works.

Configuration block.block.bartik_search_form depends on the bartik theme that will not be installed after import.
Configuration block.block.bartik_statistics_popular depends on the bartik theme that will not be installed after import.
Configuration block.block.bartik_system_main depends on the bartik theme that will not be installed after import.
Configuration block.block.bluemarine_user_login depends on the bluemarine theme that will not be installed after import.
Configuration block.block.garland_system_main depends on the garland theme that will not be installed after import.
Configuration block.block.pushbutton_user_login depends on the pushbutton theme that will not be installed after import.

I'm importing a single "view" configuration that depends on nothing, but this config import is blocked because of a lingering and totally unrelated theme setting? Unbelivable. Why is there no link on the page - "how to solve this" or a "skip" button to proceed and do not care about a theme that no longer exist?

I just updated a site from Drupal 7 to Drupal 10 (it was started in Drupal 5). It wasn't under version control until now, and when I tried running my first drush config:import on the server, trying to do a simple configuration update, I got these errors:

Configuration block.block.bartik_block_4 depends on the bartik theme ...
Configuration block.block.bartik_system_main depends on the bartik theme ...
Configuration block.block.bartik_system_powered_by depends on the bartik theme ...
Configuration block.block.bartik_user_login depends on the bartik theme ...
Configuration block.block.bluemarine_system_powered_by depends on the bluemarine theme ...
Configuration block.block.bootstrap_block_3 depends on the bootstrap theme ...
Configuration block.block.bootstrap_block_6 depends on the bootstrap theme ...
Configuration block.block.bootstrap_system_main depends on the bootstrap theme ...
Configuration block.block.deco_block_3 depends on the deco theme ...
Configuration block.block.deco_system_main depends on the deco theme ...
Configuration block.block.garland_block_4 depends on the garland theme ...
Configuration block.block.garland_system_main depends on the garland theme ...
Configuration block.block.garland_system_powered_by depends on the garland theme ...
Configuration block.block.garland_user_login depends on the garland theme ...
Configuration bootstrap.settings depends on the bootstrap extension ...
Configuration deco.settings depends on the deco extension ...

The solution:

1. Local development: Delete the config files from the configuration folder, block.block.bartik_block_4.yml, block.block.bartik_system_main.yml, etc.
2. Do an import, to delete these blocks from the Drupal 10 database configuration:
   

   $ drush config:import
    [notice] Synchronized configuration: delete block.block.bartik_user_login.
    [notice] Synchronized configuration: delete block.block.bootstrap_block_3.
    [notice] Synchronized configuration: delete block.block.deco_block_3.
    [notice] Synchronized configuration: delete block.block.garland_user_login.
    [notice] Synchronized configuration: delete block.block.bartik_block_4.
    [notice] Synchronized configuration: delete block.block.bartik_system_main.
    [notice] Synchronized configuration: delete block.block.bartik_system_powered_by.
    [notice] Synchronized configuration: delete block.block.bluemarine_system_powered_by.
    [notice] Synchronized configuration: delete block.block.bootstrap_system_main.
    [notice] Synchronized configuration: delete block.block.deco_system_main.
    [notice] Synchronized configuration: delete block.block.garland_block_4.
    [notice] Synchronized configuration: delete block.block.garland_system_main.
    [notice] Synchronized configuration: delete block.block.garland_system_powered_by.
    [notice] Synchronized configuration: delete deco.settings.
    [notice] Synchronized configuration: delete bootstrap.settings.
    [notice] Synchronized configuration: delete block.block.bootstrap_block_6.
    [notice] Finalizing configuration synchronization.
    [success] The configuration was imported successfully.
   

3. Git commit these changes, and push it to the server
4. Run the config import again on the server, it should now go through

Updated the IS with the workarounds I found in the comments.

I think it s time to close this. The only comments here since 2021 are about migrations. And support for migrations is better handled in the @migration channel in Drupal Slack.

I agree this issue is mainly about Migrations, even back in 2016, so moving to that Component, and closing it since there are solutions.

Adding a link to the Drupal Migrate issue queue, since not everyone is on Slack. Also, Slack content isn't crawled by the search engines, so harder to discover. This page -- conversely -- stays here forever, and will always be discoverable.

I agree with @larowlan in that this isn't a bug. Both the configuration system and the migration system are working as intended.

You're, let's change it back. As a user, it does look like a bug, since you are following the steps, and get an error. But the code will not be updated, because it behaves as expected -- so in that sense, the code is not buggy.

Automatically closed - issue fixed for 2 weeks with no activity.