Type.from_json() is trying to do too much

[dimaqq]

Description

jRPC responses are pumped through SomeResult.from_json(data) to convert dicts to proper data classes.

the from_json() classmethod though is capable of doing so many different things...

• it can accept the class itself, returns data unchanged
• it can accept a plain string, which would be assumed to be JSON and then:
• it can accept a dict, which would be converted to this data class, processing properties recursively
• it can accept a list, which merged elements' content into a single dict, WAT?
• it can accept "other", returning None

this means that the classmethod has a weird return type, Self|None which has cascading effects on all the users of any facade call.

Urgency

Casually reporting

Python-libjuju version

3.5.2

Juju version

any

Reproduce / Test

class ApplicationInfoResults(Type):
      _toSchema = {'results': 'results'}
      _toPy = {'results': 'results'}
      def __init__(self, results=None, **unknown_fields):
          '''
          results : typing.Sequence[~ApplicationInfoResult]
          '''
          results_ = [ApplicationInfoResult.from_json(o) for o in results or []]

          # Validate arguments against known Juju API types.
          if results_ is not None and not isinstance(results_, (bytes, str, list)):
              raise Exception("Expected results_ to be a Sequence, received: {}".format(type(results_)))

          self.results = results_
          from typing import reveal_type
W         reveal_type(self.results) # W: Type of "self.results" is "list[ApplicationInfoResult | None]"
          self.unknown_fields = unknown_fields

[dimaqq]

Original commit 9c204c0a