Can't Merge Branch When Interfaces Have Custom Fields

[adparis99]

Plugin Version

0.4.0

NetBox Version

4.1.0

Python Version

3.10.12

Steps to Reproduce

1. Create an optional custom field on the interface model
2. Create and activate a new branch
3. Create new interfaces (in my case associated with a few newly created devices). The custom field is not populated.
4. Attempt to merge branch

Expected Behavior

The branch should merge successfully.

Observed Behavior

I receive essentially the same error mentioned in issue #80:

{
    "log": [
        "Merging branch COR - New Equipment (branch_38u5jdzs)",
        "Found 247 changes to merge",
        "Setting branch status to merging",
        "Interface has no field named 'custom_fields'"
    ]
}

Edit: Added clarification that the custom field was not required nor populated for the newly created interfaces.
Edit 2: Added additional findings and steps to reproduce below.

[adparis99]

After some more trial and error, I've found a more specific set of Steps to Reproduce. It seems like if I simply create those interfaces and do nothing else, merges go through. But if I adjust an attribute (the ones I've tested being description and mac), then I get the error above.

Steps to Reproduce

1. Create an optional custom field on the interface model
2. Create and activate a new branch
3. Create new interfaces (in my case associated with a few newly created devices). The custom field is not populated.
4. Edit an attribute of the interface (for example, the description)
5. Attempt to merge branch

[adparis99]

One more thing I noticed in troubleshooting - based on the Changes Ahead tab, it seems that when the objects are initially created in a branch, their custom_felds attribute is completely empty. It's not until I edit and save an interface that custom_fields are filled with the default None value.

[jeremystretch]

I'm still having trouble narrowing down the exact steps needed to reproduce this. Currently waiting on the fix for #102 to be merged, which will assist in troubleshooting.

[jeremystretch]

Ok, I'm able to consistently reproduce this now by doing the following:

1. Create an optional custom field on the interface model
2. Create and activate a new branch
3. Edit an existing interface and set a value for the custom field
4. Attempt to merge the branch

This raises the exception:

FieldDoesNotExist("Interface has no field named 'custom_fields'")

Strangely, this does not occur when creating a new interface with the custom field value.