return 400 status code on bad arguments instead of 403 status code

[samuelstroschein]

2. Telefunc aborts function calls with bad arguments with status code 403 instead of 400

Telefunc generates shield functions for arguments automatically. But, passing bad arguments to an API call is not a 403 (forbidden) but a 400 (bad request) status code. The 403 status code lead to an hour-long wandering path that the problem was related to auth.

Originally posted by @samuelstroschein in https://github.com/brillout/telefunc/issues/56#issuecomment-1397929356

Proposal

Auto-generated shield functions that protect function arguments should return / throw a 400 (bad request) status code instead of a 403 (permission denied) status code.

[samuelstroschein]

The current 403 implementation is a footgun. TypeScript does not lint "redundant" arguments but telefunc throws a 403 on redundant arguments.

[brillout]

I agree these kind of situations should be easy to debug.

I've a couple of ideas to improve the situation.

[brillout]

I've a couple of ideas to improve the situation.

I'll implement them after I finish VPS's V1 design.