I was updating my old D projects. Surprisingly... or not, I found one that outputs a linker error. Though, I clearly remember it compiled perfectly fine the last time I worked on it. It is a GTKD project using DUB.

DUB output:

Linking...
Undefined symbols for architecture x86_64:
  "__D3std4file11DirIterator15__fieldPostblitMFNaNbNiNlZv", referenced from:
      __D3std9algorithm9iteration__T6filterS3app7listdirFAyaZ9__lambda2Z__TQBnTSQCt4file11DirIteratorZQCoMFQBcZSQDzQDyQDr__T12FilterResultSQDrQDqFQDlZQDlTQCxZQBi in extension-er.o
      __D3std9algorithm9iteration__T12FilterResultS3app7listdirFAyaZ9__lambda2TSQCt4file11DirIteratorZQCo6__ctorMFNcQBlZSQEiQEhQEa__TQDtSQDiQDhFQDcZQDcTQCvZQEq in extension-er.o
      __D3std9algorithm9iteration__T12FilterResultS3app7listdirFAyaZ9__lambda2TSQCt4file11DirIteratorZQCo6__ctorMFNcQBlbZSQEjQEiQEb__TQDuSQDjQDiFQDdZQDdTQCwZQEr in extension-er.o
      __D3std9algorithm9iteration__T12FilterResultS3app7listdirFAyaZ9__lambda2TSQCt4file11DirIteratorZQCo15__fieldPostblitMFNaNbNiNlZv in extension-er.o
      __D32TypeInfo_S3std4file11DirIterator6__initZ in extension-er.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Error: linker exited with status 1

If I'm not mistaken, this cryptic message tries to tell me that something is wrong with the standard library functions: Undefined symbols... But what's wrong exactly?

Any directions?

Any help solving this issue is greatly appreciated.

On Thursday, 5 August 2021 at 10:05:28 UTC, Ki Rill wrote:

Pretty hard to know what got wrong without log. First question would be, did you do dub -f to make sure you were not linking with stale object file ? Better yet, did you try compiling from a clean checkout ?
A link to the code and a CI run that fails in the same way would be best.

On Thursday, 5 August 2021 at 10:15:47 UTC, Mathias LANG wrote:

Yes, I tried. It didn't help. I have another active GTKD project and it compiles successfully with the same dub.json settings.

Here is the link to the code.

On 8/5/21 6:50 AM, Ki Rill wrote:

I git-cloned and built with dub on ubuntu 20.04. DMD version 2.097.0. Linked, no errors.

Not sure if it helps you, but it is a data point.

Any time I've had errors like that, I've just removed my ~/.dub directory, and the one in the project and it seems to help clear it up.

Note that the linker error you are getting is from Phobos (you can use ddemangle command line tool to see the actual symbol name), so it seems like you could be compiling against one version of Phobos, and then linking against another? How do you install your compiler? I recommend dvm if you are using dmd.

-Steve

On Thursday, 5 August 2021 at 11:43:25 UTC, Steven Schveighoffer wrote:

Unfortunately, removing ~/.dub and .dub in the project's folder did not help.

It is indeed from Phobos, it's the listdir function that is the source of the problem here. But I cannot understand why it's the problem. That function does compile on its own. It's when I put it together with GTKD it refuses to compile. Hmm...

This is a wonderful thing! How come I didn't hear about it before this day...

On Thursday, 5 August 2021 at 11:43:25 UTC, Steven Schveighoffer wrote:

I installed dmd2.97.x using brew.

On 8/5/21 9:57 AM, Ki Rill wrote:

I would recommend downloading the binaries from the dlang.org page.

I barely ever use homebrew on my mac, which means any time I want to use it, it takes hours to go through updates first!

But downloading directly from dlang.org would at least be a sanity check. It might be a homebrew issue.

-Steve

On Thursday, 5 August 2021 at 14:40:58 UTC, Steven Schveighoffer wrote:

That solved it! It is indeed homebrew.

Thank you!