hydra.searchpath vs --config-dir

[jchia]

I found that on the command-line --config-dir /some/dir is not the same as hydra.searchpath=[file:///some/dir].

If there is a top-level config file /some/dir/hyd.yml and my app uses @hydra.main(version_base='1.2', config_name='hyd'), the --config-dir works and the hydra.searchpath fails. It fails to find the config file with a hydra.errors.MissingConfigException.

A superficial reading of https://hydra.cc/docs/advanced/search_path/ suggests that hydra.searchpath=[file:///some/dir] should work. What am I missing?

[Jasha10]

I can reproduce the behavior you've described.
I believe this fails because overriding hydra.searchpath (either at the command line or within your primary config) will only affect discovery of non-primary configs. Looking at Hydra's implementation, it seems to me that the primary config must be in the directory indicated by --config-dir or by the config_path argument to hydra.main.

@hydra.main(version_base='1.2', config_name='hyd', config_path='.')

The searchpath is then computed based on what is found in the primary config. This searchpath may be overridden at the CLI, but the primary config is already loaded (or, in your case, failed to load) by the time that the CLI override is processed.

[jchia]

Then, it may be helpful for the documentation to say that searchpath does not apply to the primary config. I'm new to Hydra, but I did not get this from reading the current documentation.

Would a PR for such a documentation change be welcome?

[Jasha10]

Yes, that would be welcome!