On Thu, Sep 01, 2022 at 09:40:05PM -0000, Steve Jorgensen wrote:
I frequently find that I want to raise an exception when the target of a call is not in an appropriate state to perform the requested operation. Rather than choosing between `Exception` or defining a custom exception, it would be nice if there were a built-in `InvalidStateError` exception that my code could raise.
If the target of the call isn't in an appropriate state, isn't that a bug in the constructor that it allows you to construct objects that are in an invalid state? You should fix the object so that it is never in an invalid state rather than blaming the caller. I believe that the interpreter may sometimes raise RuntimeError for cases where objects are in a broken internal state, but I've never seen one in real life. Oh, no, I was thinking of SystemError. Nevertheless, for my own classes, I've sometimes used RuntimeError for broken internal state. I have always considered that a bug in my code.
In cases where I want to define a custom exception anyway, I think it would be nice if it could have a generic `InvalidStateError` exception class for it to inherit from.
What functionality do you expect this InvalidStateError superclass to provide that isn't already provided by Exception? -- Steve