Can't reset object attribute to its initial value.

[endreszabo]

pynetbox version

v7.0.1

NetBox version

v3.6.1

Python version

3.11

Steps to Reproduce

Consider this simple modifying of a given attribute:

>>> import pynetbox
>>> nb=pynetbox.api('http://127.0.0.1:8000', 'yada')
>>> br_native = nb.dcim.interfaces.get(id=411)
>>> eth3 = nb.dcim.interfaces.get(id=415)
>>> eth3.bridge
br-native
>>> eth3.bridge = None
>>> eth3.save()
True
>>> eth3.bridge = br_native
>>> eth3.save()
False

#and, for added confusion, changing to another bridge works again.
>>> br_users = nb.dcim.interfaces.get(id=412)
>>> eth3.bridge = br_users
>>> eth3.save()
True

Expected Behavior

This happens because _diff() in response.py returns False as the desired state matches its initial internal state, coming from the _init_cache list.

We've been here many times. Yes, I know I should have called .full_details() after the .save() to have the attributes fetched and populated again. Yes, I know pynetbox is not an ORM and it just abstracts API calls, but let's be honest, this whole way of working is highly misleading, especially for newbies.

Observed Behavior

I propose to:

• mention this behavior in the documentation,
• or add Api an option that makes pynetbox reload the object once it was saved or updated, like this: nb=pynetbox.api('http://127.0.0.1:8000', 'yada', always_reload=True)
• or rename/alias this full_details() to reload() or something else that makes more sense
• or have the Record update its own _init_cache. I know this is hard/impossible without getting back the object from NetBox and doing so would incur performance penalties; hence, I don't recommend it to be enabled by default.

[m0nkeyc0de]

I ran exactly in the same issue when assigning tags on interfaces. The save() method lets the Record object in a broken state as _diff() method still detects changes after saving:

>>> tag_network = netbox.extras.tags.get(id=237)
>>> intf = netbox.dcim.interfaces.get(id=39525)
>>> intf.tags
[]
>>> intf.tags = [tag_network]
>>> intf._diff()
{'tags'}
>>> 
>>> 
>>> intf.save()
True
>>> intf._diff()
{'tags'}
>>> 

When calling full_details() after save() the issue does not happen:

>>> intf = netbox.dcim.interfaces.get(id=39525)
>>> tag_network = netbox.extras.tags.get(id=237)
>>> 
>>> intf.tags 
[role:network]
>>> intf.tags = []
>>> intf.save()
True
>>> intf.full_details()
True
>>> intf.tags
[]
>>> intf.tags = [tag_network]
>>> intf.save()
True
>>> 

It looks like self._init_cache is not updated correctly after save() ist executed and the serialize(init=True) returns wrong data

pynetbox/pynetbox/core/response.py

Lines 505 to 506 in 97f1e8b

	if init:
	init_vals = dict(self._init_cache)

And with this wrong data the _diff() function can only have trouble to correctly detect changes.

pynetbox/pynetbox/core/response.py

Lines 538 to 540 in 97f1e8b

	init = Hashabledict(
	{fmt_dict(k, v) for k, v in self.serialize(init=True).items()}
	)

self._init_cache is popultated when _add_cache() is called

pynetbox/pynetbox/core/response.py

Lines 377 to 379 in 97f1e8b

	def _add_cache(self, item):
	key, value = item
	self._init_cache.append((key, get_return(value)))

_add_cache() is only called in _parse_values() which is only called in __init__() and in full_details(), but unfortunately this is never done after save().

The simplest way to solve this consistency issue is to call full_details() just before returning True in save()

pynetbox/pynetbox/core/response.py

Lines 592 to 593 in 97f1e8b

	if req.patch(updates):
	return True

You can assign the issue to me and I'll fix it that way, unless you have a better solution.