Editing an unterminated cable throws exception

[dutchman80]

NetBox version

v3.4.0

Python version

3.9

Steps to Reproduce

1. Create Device-A with Interface
2. Create Device-B with Interface
3. Connect Device-A to Device-B via their interfaces. Cable-1 is automatically created
4. Delete Device-A
5. Navigate to view for Cable-1 and hit the "Edit" button

Expected Behavior

The "Edit" view for the cable is displayed

Observed Behavior

<class 'AttributeError'>

'str' object has no attribute 'label'

[jeremystretch]

The error occurs during form rendering because we're unable to determine the type of the A side connection when no A side terminations exist. I'm not sure there's any particularly clever solution to this, however it may be rendered moot depending on what changes (if any) we decide to make with respect to #10769. I'm going to mark this as blocked for now pending the outcome of that issue.

[DanSheps]

So, I keep hitting this, and I am wondering if it wouldn't be worth it to turn every "interface" into a polymorphic object (yes, I am bringing up polymorphism again. :D)

The advantage, is we could likely do-away with multiple forms for connecting interfaces, front/rear ports, etc and just point to a "Connection Point" base class, which would hold the PK for whatever it morphs into (FrontPort). This would allow us to simplifiy the cable create form by consolidating the form creation logic into a single DynamicModelChoiceField.

We then wouldn't need to "determine" what type of connection we are making, we just need to allow you to connect to perhaps a base connection type (power only to power). Just a thought.

The only problem is it looks like django-polymorphic is abandoned right now.