Posted circuit terminations not appearing in circuit detail view

NetBox version

v3.0.8

Python version

3.9

Steps to Reproduce

Start fresh netbox instance.
Populate netbox db with testdata: (create all attrbutes with only the required fields.)

• Create a Provider
• Create a Site
• Create a Circuit Type
• Create a Circuit (with the provider and circuit type just created)
• Create a Provider Network
• Create a token from the admin dashboard. (I put this in .env file under variable NETBOX_TOKEN)

Since this is a fresh NetBox instance all ids should start on id: int = 1.

By using requests we post termination Z & A to the newly created circuit:

from decouple import config
import requests
import json


headers = {
    'Authorization': f'Token {config("NETBOX_TOKEN")}',
    'Content-Type': 'application/json',
    "Accept": "application/json; indent=4"
}

data = [
{'circuit': 1, 'site': 1, 'term_side': 'A'}, 
{'circuit': 1, 'provider_network': 1, 'term_side': 'Z'}
]

response = requests.post(
  f'{netbox_env}/api/circuits/circuit-terminations/', 
  headers=headers,
  data=json.dumps(data)
  )
# output is indeed a 201 response.

Expected Behavior

Both circuit termination points (A & Z) to be linked to the circuit with id: 1, and appearing in the circuit view under: /circuits/circuits/1/.

Observed Behavior

Both circuit terminations are indeed in the /api/circuits/circuit-terminations/ endpoint. However, if we go to: /circuits/circuits/1/, only the termination Z side appears. Picture to illustrate:

If I also visit the terminal checking this specific circuit instance (id:1) I found that there is no termination_a_side. ref: (terminal screen shot)

Finally, the posted data is tested being posted as singles. This also works fine.

Thank you for taking the time to read this!

[jeremystretch]

@PerAStad thank you for the thorough bug report!

When a circuit termination gets created, the relevant foreign key (termination_a or termination_b) gets updated on its parent circuit. But because we're creating two terminations at once, using two "copies" of the parent circuit, we're saving it twice. The first time, termination_a is set to the ID of the new CircuitTermination, and termination_b is null. The second time, termination_a is null and termination_b is set, which is how we end up in this state.

Seems like an easy fix though: We just need to call refresh_from_db() on the parent circuit instance prior to each save, to ensure that we're working with the most recent copy.