Why are Exceptions said to be so bad for Input Validation?

Question

I understand that \"Exceptions are for exceptional cases\" [a], but besides just being repeated over and over again, I\'ve never found an actual reason for this fact.

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Answer 1

This is a linguistic pov( point of view) on the matter.

Why are Exceptions said to be so bad for Input Validation?

conclusion :

• Exceptions are not defined clearly enough, so there are different opinions.
• Wrong input is seen as a normal thing, not as an exception.

thoughts ?

It probably comes down to the expectations one takes about the code that is created.

• the client can not be trusted
  • validation has to happen at the server's side. stronger : every validation happens at server's side.
  • because validation happens at the server's side it is expected to be done there and what is expected is not an exception, since it is expected.

However,

• the client's input can not to be trusted
• the client's input-validation can be trusted
  • if validation is trusted it can be expected to produce valid input
  • now every input is expected to be valid
  • invalid input is now unexpected, an exception

.

exceptions can be a nice way to exit the code.

A thing mentioned to consider is if your code is left in a proper state. I would not know what would leave my code in an improper state. Connections get closed automatically, leftover variables are garbage-collected, what's the problem?