[Bug d/103728] New: Allow to run unittests before main()

[Bug d/103728] New: Allow to run unittests before main()

[pierrick.bouvier at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103728

            Bug ID: 103728
           Summary: Allow to run unittests before main()
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: d
          Assignee: ibuclaw at gdcproject dot org
          Reporter: pierrick.bouvier at posteo dot net
  Target Milestone: ---

With gdc-12, semantic of unittests will change to match dmd behavior.

So far (<= gdc-11), option -funittest could be used to:
- compile unittest
- automatically run them before main

>From gdc-12, semantic will be:
- compile unittest
- only run them

For users using dub (test), it may sound like the good choice. But for all
others (we use meson), this change is really a burden.

---

>From this post:
https://forum.dlang.org/thread/jrnyklhuqadormjmelae@forum.dlang.org

someone suggested to use this:
version (unittest) extern(C) __gshared string[] rt_options = [
"testmode=run-main" ];

It works well with gdc-12, but it is very cryptic and still hard to add in all
our binaries (we have dozens).

---

Would you consider to add an option -funittest-and-run-main (or similar), to
allow for that thanks to a compiler switch?

Thanks for your hard work on gdc and porting to new front-end.

[Bug d/103728] Allow to run unittests before main()

[ibuclaw at gdcproject dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103728

--- Comment #1 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
Not sure if there'd be much help from the compiler on this front, as it's a
runtime library feature that unittests are executed in the first place - the
compiler simply generates functions in the proper place for the library to find
them.

See
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=libphobos/libdruntime/rt/dmain2.d;h=b363e3fea4fc55d9f6941030dc808e5129bd38c2;hb=HEAD#l491

The old behaviour was of `runAll()` was:

    if (rt_init() && runModuleUnitTests())
        tryExec({ result = mainFunc(args); });

> someone suggested to use this:
> version (unittest) extern(C) __gshared string[] rt_options = [ "testmode=run-
> main" ];
> It works well with gdc-12, but it is very cryptic and still hard to add in all
> our binaries (we have dozens).
A second way of doing the would be to run the program with the command-line
option: --DRT-testmode=run-main

The options itself gets filtered from the `string[] args` parameter of D main,
so it won't affect tests where arguments are given to binaries (unless the
--DRT option appears after `--`).

[Bug d/103728] Allow to run unittests before main()

[pierrick.bouvier at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103728

--- Comment #2 from Pierrick Bouvier <pierrick.bouvier at posteo dot net> ---
Problem with command line approach is that it implies to patch all our scripts,
which is *really* boring. At this point, manually adding rt_options string in
all binaries is easier.

Alas, there is no environment variable for controlling this.

When unittests semantic was changed in dmd, from what I read, dmd maintainers
were not open to keep an "old" mode as a compiler option.

I understand it's not the role of gdc to control this, but I still think it
could be useful to offer a flag (that automatically generates rt_options
symbol).

[Bug d/103728] Allow to run unittests before main()

[ibuclaw at gdcproject dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103728

--- Comment #3 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
(In reply to Pierrick Bouvier from comment #2)
> Problem with command line approach is that it implies to patch all our
> scripts, which is *really* boring. At this point, manually adding rt_options
> string in all binaries is easier.
> 
> Alas, there is no environment variable for controlling this.
Environment variables can be used if you declare:
```
extern(C) __gshared bool rt_envvars_enabled = true;
```
Then DRT_testmode=run-main should work.

[Bug d/103728] Allow to run unittests before main()

[pierrick.bouvier at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103728

--- Comment #4 from Pierrick Bouvier <pierrick.bouvier at posteo dot net> ---
Thanks for your suggestion.

We will follow this to upgrade our compiler.

[Bug d/103728] Allow to run unittests before main()

[pierrick.bouvier at posteo dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103728

Pierrick Bouvier <pierrick.bouvier at posteo dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #5 from Pierrick Bouvier <pierrick.bouvier at posteo dot net> ---
gdc does not have to support this use case, since it is related to D runtime.