config: Remove confusing magic in path handling

1. When passed a .yaml path (or any path with a non-whitelisted extension), don't read .yml instead when the .yaml exists. It's an extremely surprising behavior.

2. If the .yaml file does not exist, it will still try alternative extensions in order not to break existing deployments which may rely on it, but it raises a warning now.

3. When given a non-existing path, show an error log, but keep parsing it as an empty config, in order not to break existing deployments.

Jenkins job DCORE/gitlab-builds #69 succeeded .
See Console Output and Coverage Report for more details.

LGTM, should we also whitelist the .yaml extension by adding it in the SWH_CONFIG_EXTENSIONS list ?

IMO, no, because I'd like to remove this entirely.

approved this merge request

approved this merge request

Thanks for improving that left-over mess from years ago.

That started from .ini file, & then yaml support was added, 'yml' probably to keep the same number as 'ini' or something... Then moving to yaml altogether (dropping ini) but we never cleaned that up completely. Now that we got tests & sentry, that should raise eyebrows more easily in case of breaking... (if you had not implemented the retro-compat' code part that is).

merged