to my current understanding a plugin will be checked and tested after it has been submitted and before it appears as a beta version in the plugin store.
This is correct. After the first submission it will be tested before it is available. Subsequent versions will be availbe directly in the beta channel. After beta testing is done it will be promoted to the stable channel
If I fix an issue in a plugin I have already submitted, but which is not in the plugin store even as a beta version yet: How would one deal with it?
Plugins can be updated with the same procedure as the first submission. We will always test the latest version.
As there is no option to “revoke” a submitted (but not yet published) plugin, would I have to submit the plugin again (using a new version number)?
There is no revoke option yet, this will be available later in MyVolumio. Until then, just update the version and if it is really nescessary, contact us to remove the version from the database.
What would happen to the previously submitted version? Will it be sorted out “automatically” so it doesn’t get into the plugin store?
The previously submitted version will be visible from the ‘Details’ page of the plugin (latest 5 are always available to provide a downgrade option). The download button on the main page will always download the latest version.
At the moment I share @patrickkfkan’s fear that the content of the repository and the submitted plugins will diverge earlier or later.
The ‘volumio plugin submit’ command checks if the source it is submitted from is staged, committed and pushed, and that the repository used is a fork of the volumio-plugins-sources repo. We will check manually if the pull request was submitted. This should always keep the plugin package in the store in sync with it’s repository.