Full Proper Logging about pedal

[acbart]

This dovetails with error handling. What kind of errors do we have in Pedal?

• Student code errors are things that should be transformed into feedback. Student errors should never stop the ICS.
• System errors are bad and should probably give a productive error message.
• Instructor Control Script errors are also bad and should probably give a productive error message.

The latter two kinds of errors should be raised, that seems clear enough. And I guess logged? Or one of the other? I need to think a bit more about what this should look like exactly. Can we think of some cases of actual errors?

It's confusing because usually catchable exceptions are because you know the user can get things into an invalid state. But what situations in Pedal allow the instructor to get things into a bad state? Let's think about each tool:

• TIFA: This has no configuration, so that's not very exciting. It can have errors in some places, I guess, but those are things to fix in the code rather than to just raise as errors, aren't they?
• Sandbox: Perhaps if you set up an input wrong?
• Assertions: Ah, yes, here's something where the user can make many mistakes regarding the values, right? They could pass in something that doesn't work in a context? But shouldn't we do type changes until something works? It's simpler for some of the cases where an invalid value is more likely, I suppose (e.g., didn't pass in a valid node name to prevent_ast).

So many of Pedal's tools are unconditional executions. You just call them and let them work. That's a tricky part of all this.