Optional arguments to rasa data convert are not optional

[kaiogu]

Rasa version:
2.0.6
Rasa SDK version (if used & relevant):

Rasa X version (if used & relevant):

Python version:
3.8.0
Operating system (windows, osx, ...):
ubuntu 18.04
Issue:
Arguments stated to be optional by the rasa data convert xxx help are not actually optional.

Error (including full traceback):

❯ rasa data convert nlu
usage: rasa data convert nlu [-h] [-v] [-vv] [--quiet] -f {json,md,yaml} --data DATA --out OUT [-l LANGUAGE]
rasa data convert nlu: error: the following arguments are required: -f/--format, --data, --out

Contrast this with the help of the same command in which these arguments are stated to be optional and to have defaults:

❯ rasa data convert nlu --help
usage: rasa data convert nlu [-h] [-v] [-vv] [--quiet] -f {json,md,yaml} --data DATA --out OUT [-l LANGUAGE]

optional arguments:
  -h, --help            show this help message and exit
  -f {json,md,yaml}, --format {json,md,yaml}
                        Output format the training data should be converted into. Note: currently training data can be
                        converted to 'yaml' format only from 'md' format (default: yaml)
  --data DATA           Path to the file or directory containing Rasa NLU data. (default: data)
  --out OUT             File (for `json` and `md`) or existing path (for `yaml`) where to save training data in Rasa
                        format. (default: converted_data)
  -l LANGUAGE, --language LANGUAGE
                        Language of data. (default: en)

Command or request that led to error:

❯ rasa data convert nlu
❯ rasa data convert nlg
❯ rasa data convert core

Content of configuration file (config.yml) (if relevant):

Content of domain file (domain.yml) (if relevant):

Definition of Done
For all rasa data convert commands:

• set required=False (or don't set it) if a default was provided

[sara-tagger]

Thanks for the issue, @amn41 will get back to you about it soon!

You may find help in the docs and the forum, too 🤗

[wochinge]

The issue is that we mark things as required but give them defaults at the same type. Argparse treats everything with a default as required=False as optional but then still fails if not provided 🤦🏻