creating Config without path raises unhandled TypeError

[btel]

this only happens if QUETZ_CONFIG_FILE is not defined

import os; os.listdir()
from quetz import config
config.Config()

gives this error

['channels', 'quetz.sqlite', 'quetz.log', 'config.toml']

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/bartosz/repos/libraries/mamba-org/quetz/quetz/config.py", line 140, in __new__
    path = os.path.abspath(cls.find_file(deployment_config))
  File "/home/bartosz/.pyenv/versions/micromamba/envs/quetz/lib/python3.8/posixpath.py", line 374, in abspath
    path = os.fspath(path)
TypeError: expected str, bytes or os.PathLike object, not NoneType

but this works:

>>> os.environ['QUETZ_CONFIG_FILE'] = 'config.toml'
>>> config.Config()
<quetz.config.Config object at 0x7f8885b89610>

What needs to be done

catch the exception and ask user to provide the name or path of config file using env var

Remarks

quetz run/start configures the QUETZ_CONFIG_FILE automatically

[madhur-tandon]

Should we put the call to config.Config() in a try block in all places?
Ideally this should be done only once right? And then propagated to all other places where it's needed.

[btel]

no it should be done in Config class, about here:

File "/home/bartosz/repos/libraries/mamba-org/quetz/quetz/config.py", line 140, in __new__
    path = os.path.abspath(cls.find_file(deployment_config))

[madhur-tandon]

yeah, thanks. This is exactly what I meant by doing it at one place - which is propagated to everywhere we call Config().
I am picking this up. Will send a PR soon.