Bad array indexing is considered deadly

[Paolo Invernizzi via Digitalmars-d]

On Saturday, 3 June 2017 at 10:47:36 UTC, Ola Fosheim Grøstad 
wrote:
> On Saturday, 3 June 2017 at 10:21:03 UTC, Paolo Invernizzi 
> wrote:
>> It doesn't seems to me that the trends to try to handle 
>> somehow, that something, somewhere, who knows when, has gone 
>> wild it's coherent with the term "robustness".
>
> That all depends. It makes perfect sense in a "strongly pure" 
> function to just return an exception for basically anything 
> that went wrong in that function.
>
> I use this strategy in other languages for writing 
> validator_functions, it is a very useful and time-saving way of 
> writing validators. E.g.:
>
> try {
>     …
>     validated_field = validate_input(unvalidated_input);
> }
>
> I don't really care why validate_input failed, even if it was a 
> logic flaws in the "validate_input" code itself it is perfectly 
> fine to just respond to the exception, log the failure return a 
> failure status code and continue with the next request.
>
> The idea that programs can do provably full veracity checking 
> of input isn't realistic in evolving code bases that need 
> constant updates.

Sorry Ola, I can't support that way of working.

Don't take it wrong, Walter is doing a lot on @safe, but 
compilers are built from a codebase, and the codebase has, 
anyway, bugs.

I can't approve a "ok, do whatever you want in the validate_input 
and I try to *safely* throw"

IMHO you can only do that if the validator is totally segregated, 
and to me that means in a separate process, neither in another 
thread.

>> I'm trying to exactly do that, I like to think myself as a 
>> very pragmatic person...
>
> What do you mean by "pragmatic"? Shutting down a B2B website 
> because one insignificant request-handler fails on some 
> requests (e.g. requesting a help page)  is not very pragmatic.
>
> Pragmatic in this context would be to specify which handlers 
> are critical and which ones are not.

To me, pragmatic means that the B2B website has to be organised 
in a way that the impact is minimum if one of the processes that 
are handling the requests are restarted, for a bug or not. See 
Laeeth [1]. Just handle "insignificant requests" to a cheeper, 
less robust, less costly, web stack.

But we were talking about another argument...

/Paolo

[1] 
http://forum.dlang.org/post/uvhlxtolghfydydoxwfg@forum.dlang.org