I use run.dlang.io often to test things, and then when I see they are broken, I change to "all compilers" to see when it might have broken/changed.

However, there are two limits that frustrate this process:

1. There is a limit to the amount of output that can be shown. If your test case spits out a bunch of text that changes from version to version (i.e. a big exception trace with differing line numbers), then it will truncate the result, potentially hiding the place where the issue lies.
2. There is a limit to the time your request can take. The reasons for this are obvious.

However, I have discovered a trick to avoid these limits while still testing multiple versions. D has a __VERSION__ special token that identifies the version of the compiler. For 2.100, __VERSION__ == 2100.

Great, how can we use this?

static if(__VERSION__ >= 2100) {
   // real test code
} else void main() {}

Now, the test code only builds on versions 2.100 and above, and a quick basic program which can build and run very quickly and outputs nothing will build on prior versions.

What if the change occurred before 2.100? Simply change the range:

static if(__VERSION__ >= 2090 && __VERSION__ < 2100) {
   // real test code
} else void main() {}

Basically, this avoids the limitations, and still allows you to test simple problems with a range of D versions without having to download them locally.

-Steve

On Wednesday, 31 January 2024 at 20:33:26 UTC, matheus wrote:

2.079.1 to 2.085.1: Failure with output:
-----
onlineapp.d(1): Error: module `std` is in file 'std.d' which cannot be read
import path[0] = /path/to/dmd.linux/dmd2/linux/bin64/../../src/phobos
import path[1] = /path/to/dmd.linux/dmd2/linux/bin64/../../src/druntime/import
-----

2.086.1 to 2.099.1: Success and no output
Since      2.100.2: Success with output: Hello D

The std/package.d module was added in 2.086.0: https://dlang.org/changelog/2.086.0.html#std-all

-Steve

On Wednesday, 31 January 2024 at 19:54:24 UTC, Steven Schveighoffer wrote:

I also use it very often and I can relate.

static if(__VERSION__ >= 2100) {
   // real test code
} else void main() {}

This is what I generally do (at the very top of the file):

static if (__VERSION__ < 2100)
    void main() {}
else:

import std;

void main()
{
    // ...
}

The else: looks really awkward and hacky, but it works.

On Wednesday, 31 January 2024 at 20:56:49 UTC, Anonymouse wrote:

static if (__VERSION__ < 2100)
    void main() {}
else:

import std;

void main()
{
    // ...
}

Ah, very nice! Easy to paste this in at the top! I'll have to remember that.

It's a nice feature of static if and version that works at declaration level. This is what it is intended for (to avoid indentation issues).

-Steve