Disable automatic conversion of date strings in from_dotlist

[shuki-hpcnt]

Issue

When instantiating OmegaConf from from_dotlist, yaml loader tries to convert date-formatted strings into date type, therefore raises error when validating the type of values.

 OmegaConf.from_dotlist(["my_date=2019-11-11"])

>>>

.../site-packages/omegaconf/config.py in _prepare_value_to_add(self, key, value)
    448         if not Config.is_primitive_type(value):
    449             full_key = self.get_full_key(key)
--> 450             raise ValueError("key {}: {} is not a primitive type".format(full_key, type(value).__name__))
    451
    452         if self._get_flag('readonly'):

ValueError: key my_date: date is not a primitive type

This error also blocks the overriding of configuration values by using cli arguments in hydra.

Potential workaround

Could be solved by removing implicit timestamp resolvers in default yaml.SafeLoader.
(Related stackoverflow: https://stackoverflow.com/questions/34667108/ignore-dates-and-times-while-parsing-yaml)

[omry]

Thanks for reporting.
For now try to indicate that those are strings:

In [4]: OmegaConf.from_dotlist(["my_date=!!str 2019-11-11"])
Out[4]: {'my_date': '2019-11-11'}

This should work from command line if you wrap the key=value pair: "my_date=!!str 2019-11-11"
although I did not test yet.

I would appreciate a PR that disables it.
I am on vacation so it may be a while before I am able to fix it.

There is already some adjustments to the build in resolvers here:

https://github.com/omry/omegaconf/blob/master/omegaconf/config.py#L26-L42