odelalleau/omegaconf

Flexible Python configuration system. The last one you will ever need.

omegaconf's Issues

Deprecate `OmegaConf.is_none()

PROBLEM

With the change to OmegaConf.is_missing() in omry#545, the current behavior of OmegaConf.is_none() in OmegaConf 2.0 can be confusing (because it resolves interpolations, while OmegaConf.is_missing() doesn't).

In addition, OmegaConf.is_none() has potentially non-intuitive behavior in situations where the key can't be resolved (see below for details).

SOLUTION
OmegaConf.is_none() is being partially deprecated in OmegaConf 2.1 to have a simpler and more explicit behavior.

MIGRATION INSTRUCTIONS

Scenario 1 -- Your code is checking a specific key:

OmegaConf.is_none(cfg, "foo")
OmegaConf.is_none(cfg, key)

It is recommended to change these to:

cfg.foo is None
cfg[key] is None

Note however that when using this new syntax, an exception may be raised when accessing the key, while OmegaConf.is_none() used to silence such exceptions. If you want to keep the exact (but possibly unintuitive) behavior from before, you can implement your own is_none() function as follows:

def is_none(obj: Container, key: Union[int, DictKeyType]) -> bool:
    try:
        return obj[key] is None
    except ConfigKeyError:
        return True  # `True` if the key does not exist in the config
    except (InterpolationResolutionError, MissingMandatoryValue):
        return False  # `False` if it is either missing ("???") or an invalid interpolation

Scenario 2 -- Your code is not providing a key:

OmegaConf.is_none(obj)

It is recommended to change this check into:

OmegaConf.is_none(obj, resolve=True)

Note however that if obj is an interpolated node, an exception may be raised during interpolation resolution, while the old OmegaConf.is_none(obj) would silence it and return False. If you want to keep this behavior, then you should use:

OmegaConf.is_none(obj, resolve=True, throw_on_resolution_failure=False)

Additional context
See discussion in omry#545 (comment)

Dev note: at the same time, the internal Node._is_none() can be modified to not resolve interpolations.