assert(0) behavior

[Steven Schveighoffer via Digitalmars-d]

On 8/4/15 4:56 PM, Jonathan M Davis wrote:
> On Tuesday, 4 August 2015 at 20:48:52 UTC, Steven Schveighoffer wrote:
>> On 8/4/15 4:43 PM, Steven Schveighoffer wrote:
>>> I should say, any assert(0) with a message printed that is possible to
>>> trigger in release mode is an error. If you can ensure it's only
>>> possible to trigger when compiled in debug mode (or for unit tests),
>>> then assert(0, msg) is fine.
>>
>> In that vein, would it be possible to make this a warning? i.e. if you
>> compile a file in -release mode, and the compiler encounters an
>> assert(0, msg), it emits a warning?
>
> I fail to see why it's a problem if assert(0) has a message. It's
> exactly the same as any other assertion except that it stays even with
> -release, and you don't get the message then (whereas with a normal
> assertion, you wouldn't get anything).

Seeing an assert with a message gives the impression that you will see 
the message if you get there. I get that normal asserts may not even 
trigger. But the concept of "oh, if I see that message I know what 
happened" really goes out the window if you are never going to see it.

As I said earlier, any line in druntime that has an assert(0, msg) is a 
bug, because the message is never seen.

Doing the static if thing isn't the right answer either. The right 
answer is to choose one or the other (and by choosing to print a 
message, you could either throw an assert error directly, or print the 
message specifically and then assert(0) ).

So basically:

assert(0, msg);

becomes

printSomehow(msg);
assert(0);

With druntime it's difficult to actually print the message (and my PR is 
trying to fix that).

-Steve