[3.6.1.0] add_machine does not respect series option

[phvalguima]

Description

Juju is ignoring my request for a jammy machine and setting up ubuntu 24.04 instead.

It seems to be a very similar bug to: #1229
However, seems that #1229, the user is trying to force 24.04 and getting 22.04 machines instead.

Not sure what caused the change.

Environment

OS: Ubuntu 24.04
Juju CLI: 3.6.2 (latest/stable as of now)
Juju Controller version: 3.6.2
libjuju: 3.6.1.0
LXD: 6.2

Using LXD cloud (localhost).

RPC Request

Once I run the add_machine call, I can see the following RPC request:

DEBUG:juju.client.connection:connection id: 131775709014464 ---> {
  "type": "MachineManager",                                       
  "request": "AddMachines",                                       
  "version": 10,                                                  
  "params": {                                                     
    "params": [                                                   
      {                                                           
        "addresses": [],                                          
        "base": null,                                             
        "constraints": null,                                      
        "container-type": null,                                   
        "disks": [],                                              
        "hardware-characteristics": null,                         
        "instance-id": null,                                      
        "jobs": [                                                 
          "JobHostUnits"                                          
        ],                                                        
        "nonce": null,                                            
        "parent-id": null,                                        
        "placement": null                                         
      }                                                           
    ]                                                             
  },                                                              
  "request-id": 7                                                 
}                                                                 

Debug logs in the model: https://pastebin.ubuntu.com/p/j6xCZPB3c4/

Urgency

Annoying bug in our test suite

Python-libjuju version

3.6.1.0

Juju version

3.6.2

Reproduce / Test

# First, install libjuju:
sudo pip3 install juju==3.6.1.0


# Once that is finished, run the following python commands:
$ python3      
>>> from juju.model import Model                                       
>>> import asyncio                                                     
>>> model = Model()                                                    
>>> asyncio.run(model.connect(model_name="libjuju-issue"))  # Add your model name in this case
>>> model.name                                                         
'libjuju-issue'                                                        
>>> asyncio.run(model.add_machine(series="jammy"))

[SimonRichardson]

We should be using base (example: ubuntu@24.04) with 3.6. So we should check the facade version and ensure that we're sending base or series depending on that.

python-libjuju/juju/model/__init__.py

Lines 1574 to 1575 in 71f885b

	if series:
	params.series = series

See:

python-libjuju/juju/client/_definitions.py

Lines 575 to 587 in 71f885b

	_toSchema = {
	"addresses": "addresses",
	"base": "base",
	"constraints": "constraints",
	"container_type": "container-type",
	"disks": "disks",
	"hardware_characteristics": "hardware-characteristics",
	"instance_id": "instance-id",
	"jobs": "jobs",
	"nonce": "nonce",
	"parent_id": "parent-id",
	"placement": "placement",
	}

[dimaqq]

More context: #1229 (comment)