BUG: error messages while importing subcommand modules are suppressed

[shilorigins]

Current Behavior

If an error occurs while loading a subcommand module (e.g. bin/ui.py), the specific error message is suppressed and the program exits with a generic invalid choice message.

Expected Behavior

Errors that occur while loading subcommand modules should be shown to the user, at least when that subcommand is used.

Context / environment

During development, the obfuscation of error messages forces me to run through a debugger to reproduce the error message or to carefully inspect the file changes.

Steps to Reproduce (for bugs)

1. In the global namespace of bin/ui.py, add a line raise Exception("Reason for the error")
2. Run superscore ui
3. Note the output: 'ui' is not a valid choice, but no reason is given

Suggested Solution

[tangkong]

This is due to how we gather the sub-commands. If the subcommand throws an exception while being prepared, it's simply not prepared nor made available.

I've recently worked out a better way to build the argparser, which should speed things up and will probably also propagate errors fully. It just hasn't made its way here yet