IllegalStateException occurs when deleting repository if plugin is disabled

Summary

When trying to delete a repository of a type that is driven by a plugin, an IllegalStateException occurs with the following message if the plugin is disabled:

java.lang.IllegalStateException: Cannot load repository with key <pluginKey>. Plugins may have been disabled.

where <pluginKey> is the plugin key of the repository type in question, e.g. com.atlassian.bamboo.plugins.atlassian-bamboo-plugin-git:git for git repositories.

Steps to Reproduce

1. Stop Bamboo
2. Disable a plugin that drives a repository type that you're using in a plan
3. Start Bamboo
4. Navigate to a plan that uses a repository of a type whose plugin you disabled in step 2
5. Try to delete the repository

Expected Results

The repository is deleted.

Actual Results

The below exception occurs:

java.lang.IllegalStateException: Cannot load repository with key <pluginKey>. Plugins may have been disabled.

where <pluginKey is the plugin key of the repository type in question, e.g. com.atlassian.bamboo.plugins.atlassian-bamboo-plugin-git:git for git repositories.

Workaround

Re-enable the previously disabled plugin, then delete the repository, then disable the plugin again.