How to reproduce the issue:
- set up a tracker with two fields: a Source field and a Target Selectbox field. The Source field can be selectbox or multi-selectbox.
- choose a default value for the Target Selectbox field
- set up field dependencies from Source field to Target field. There must be at least one that targets "None"
- open the artifact modal, choose the Source value
- The Target field is empty, there is no "None" value, and there are no values to choose from. If you try to submit, the backend will reject it due to missing field dependency.
Contrary to what request #28255 says, "None" should be added even when a selectbox field has a default value. The default value should still be selected nonetheless, but the absence of "None" causes problems with field dependencies.
Field dependencies administration allows targeting "None" despite the field being required or having a default value. If we don't add "None" in those situations, it makes it impossible to submit the artifact because field dependencies will require a "None" value that is absent.
The artifact UI also adds "None" value to selectbox fields, regardless of the presence of a default value.
The issue was pre-existing (since git #tuleap/stable/702e33f9b78eb151003720c85f4a67c128a4d251) but was made visible by git #tuleap/stable/a4aa0b4475ef5ddb6cd95d689c3252db4cedf94b