Should app crash or continue on normally while noting the problem?

Question

Options:

1) When there is bad input, the app crashes and prints a message to the console saying what happened

2) When there is bad input, the app throws away the input and continues on as if nothing happened (though nothing the problem in a separate log file).

While 2 may seem like the obvious solution, the app is an engine and framework for game development, so if a user is writing something and does something wrong, it may be beneficial for that problem to be immediately obvious (app crashing) rather than it being ignored and the user potentially forgetting to check the log to see if there were any problems (may forget if the programmed behavior isn't very noticeable on screen, so he doesn't catch that it is missing).

Answer 1

There is no one-size-fits-all solution. It really depends on the situation and how bad the input is.

However, since you specifically mentioned this is for an engine or framework, then I would say it should never crash. It should raise exceptions or provide notable return codes or whatever is relevant for your environment, and then the application developer using your framework can decide how to handle. The framework itself should not make this decision for all apps that utilize the framework.

Answer 2

I would use exceptions if the language you are using allows them..

Since your framework will be used by other developers you shouldn't really constraint any approach, you should let the developers catch your exception (or errors) and manage what to do..

Answer 3

Personally I would avoid the crash approach and opt for (2) that said make sure that the error is detected and logged and above all avoid any swallowing of errors (e.g. empty catch).

It is always helpful to have some kind of tracing/logging module, for instance later when you are doing performance tuning or general troubleshooting.

Answer 4

It depends on what the problem is. When I'm programming and writing error handling I use this as my mantra:

Is this exception really exceptional?

Meaning, is the error in input or whatever condition is "not normal" recoverable? In the case of a game, a File not Found exception on a texture could be recoverable and you could show a default texture so you know something broke.

However, if you have textures in a compressed file and you keep getting checksum errors, that would be an exceptional exception and I would crash the game with the details.

It really boils down to: can the application keep running without issue?

The one exception to this rule though (ha ha) is, if something is corrupted you can no longer trust your validation methods and you should crash as quickly as you can to prevent the corruption from spreading.

Answer 5

Generally speaking nothing should crash on user input. Whether the app can continue with the error logged or stop right there is something that is useful to be able to configure.

If it's too easy to ignore errors, people will just do so, instead of fixing them. On the other hand, sometimes an error is not something you can fix, or it's totally unrelated to what you're working on, and it's holding up your current task. So it depends a bit on who the user is.

Logging libraries often let you switch logs on and off by module and severity. It might be that you want something similar, to let users configure the "stop on error" behaviour for certain modules or only when above a certain level of severity.