Custom Validations support on M2M

[michalis1]

As ...

P.D. - Nautobot App Developer

I want ...

Custom validators to be able to apply validation rules to many-to-many fields, such as prefix locations or tags.

So that ...

Custom Validators will support compliance for many-to-many fields, allowing app developers to define compliance rules for these fields.

I know this is done when...

When creating a custom validator, the self.context['object'] provides the user's selections from the form. However, for many-to-many fields like tags, instead of getting the user's current form choices, we are getting the existing data from the database. To resolve this, we need access to the many-to-many fields within self.context['object']. For example, when a user edits a prefix, self.context['object'].locations should reflect the user's current selection, not the existing locations associated with the prefix.

Optional - Feature groups this request pertains to.

• Automation
• Circuits
• DCIM
• IPAM
• Misc (including Data Sources)
• Organization
• Apps (and other Extensibility)
• Security (Secrets, etc)
• Image Management
• UI/UX
• Documentation
• Other (not directly a platform feature)

Database Changes

No additional models or fields are required.

External Dependencies

No additional external dependencies are required.

[glennmatthews]

Because updating many-to-many fields is a separate database operation from saving the object itself, this is not as straightforward to design/implement as it might seem. I get the desire/need for this functionality though.