On 09/02/2015 06:28 PM, Jack Stouffer wrote:
> I wanted some second opinions on an idea I had for D before I made a
> bugzilla issue.
>
> Currently in D, to have a statement run only in debug mode, you can mark
> it with the debug keyword. But, there is currently no way to mark a
> statement so that it only runs in release. So what I propose is a
> release statement like so:
>
> debug {
>      // only runs when -debug is given
> }
>
> release {
>      // only runs when -release is given
> }
>
> Or, if adding a new keyword to the language is a no go, it could be done
> like so:
>
> debug {
>      // only runs when -debug is given
> } else {
>      // only runs when -release is given
> }
>
> I have run into a need for this twice in one day, both having to do with
> unit tests in phobos. For the first one, I needed a way to make sure
> that a function is @nogc in release. For the other, the function I was
> tested had different outputs for release and debug if the input was an
> empty range, and I had no way to test both cases.
>

Its behaviour literally depended on the -release flag? How?

> I can think of several other use cases off the top of my head. One, If
> you have a GUI application that checks for a serial number on startup,
> there's no reason to do that check in a debug build. Or, if your making
> a game, there's no reason to do the opening logo crawl before the menu
> if your using debug mode.
>
> A rebuttal to this might be to just use version and pass something in
> during compilation. The problem that I have is this is not a solution
> for the phobos code that I am working on.

version(assert){}else{
    // only runs when -release is given
}

On Wednesday, 2 September 2015 at 19:34:53 UTC, Jack Stouffer wrote:
> On Wednesday, 2 September 2015 at 19:15:08 UTC, jmh530 wrote:
>> I wasn't familiar with version(release). Would you need to compile with -version=release then?
>
> No, it seems to work with just the -release flag.
>
> The Python programmer in me hates the inconsistency between these two, but it's fine.

It's because -debug has _nothing_ to do with "debug mode." It simply has to do with debugging. And that makes sense and is perfectly fine except that it causes confusion when you start considering -release and "release mode" - especially when folks have a tendency to call the opposite of "release mode" "debug mode." So, arguably -debug and version(debug) should have been something else in order to reduce confusion, but I honestly don't know what name to use instead, since it _is_ specifically for debugging.

- Jonathan M Davis

On Wednesday, 2 September 2015 at 16:28:12 UTC, Jack Stouffer wrote:
> I wanted some second opinions on an idea I had for D before I made a bugzilla issue.
>
> Currently in D, to have a statement run only in debug mode, you can mark it with the debug keyword. But, there is currently no way to mark a statement so that it only runs in release. So what I propose is a release statement like so:
>
> debug {
>     // only runs when -debug is given
> }
>
> release {
>     // only runs when -release is given
> }
>
> Or, if adding a new keyword to the language is a no go, it could be done like so:
>
> debug {
>     // only runs when -debug is given
> } else {
>     // only runs when -release is given
> }
>
> I have run into a need for this twice in one day, both having to do with unit tests in phobos. For the first one, I needed a way to make sure that a function is @nogc in release. For the other, the function I was tested had different outputs for release and debug if the input was an empty range, and I had no way to test both cases.
>
> I can think of several other use cases off the top of my head. One, If you have a GUI application that checks for a serial number on startup, there's no reason to do that check in a debug build. Or, if your making a game, there's no reason to do the opening logo crawl before the menu if your using debug mode.
>
> A rebuttal to this might be to just use version and pass something in during compilation. The problem that I have is this is not a solution for the phobos code that I am working on. Also, I think the first example above is very clear code and follows the debug statement's precedent.

In general, it's a really _bad_ idea to only do something in release mode. It makes it much harder to debug it when something goes wrong, and it means that what you're doing in non-release mode doesn't necessarily correspond to what happens in release mode. Normally, the only code differences between release mode and non-release mode relate to extra correctness checking - like with assertions - which get stripped out in release mode for efficiency. And many folks think that even _that_ is a bad idea.

So, I'd suggest that you reconsider even trying to do this, and doing something like having a range act differently between release and non-release modes seems like a disaster waiting to happen. At most, having assertions that get stripped out in release mode makes sense. The behavior and semantics of the code doesn't really change in that case. It's just a question of what happens when you screw up and fail the assertion (i.e. whether it's triggered and kills your program or whether it was compiled out and your program heads into undefined, buggy territory).

So, maybe you've actually found a case where it makes sense to do something in release mode but not in non-release mode, but I seriously question that it's a good idea.

- Jonathan M Davis

On 09/04/2015 04:53 PM, Jonathan M Davis wrote:
> Normally, the only code differences between release mode and non-release
> mode relate to extra correctness checking - like with assertions - which
> get stripped out in release mode for efficiency.

Failing assertions have been redefined to be undefined behaviour in -release. That's not the same as stripping them out.