Build Error when using GCC 14

[matthiasdotsh]

Hi,

I'm currently unable to build openfst/kaldi with a gcc 14.

Building openfst fails with:

/nix/store/xb8h6kfjbqclshgxq5ikh9maavxn3z1g-source/src/include/fst/fst.h:655:59: error: no match for 'operator=' (operand types are 'std::unique_ptr<fst::SymbolTable>' and 'fst::SymbolTable*')
  655 |     isymbols_ = impl.isymbols_ ? impl.isymbols_->Copy() : nullptr;
      |                                                           ^~~~~~~ 

I was able to compile kaldi with gcc14 using the following patch.

Is there any chance to get this merged into your openfst fork? Or what is the best way to fix the kaldi compilation?

[csukuangfj]

Please don't use that patch directly.

Please see
kaldi-asr/kaldi#4927 (comment)

you should use

#ifdef  xxx
#else 
#endif

[matthiasdotsh]

Thank you for fast your response, it was very helpful.

A quick follow-up question:
Do I understand correctly that you can only use openfst 1.8.4 in Kaldi if you use the "bash + Makefile" variant because there is no cmake support in the upstream openfst?

[csukuangfj]

I don't think so. I think the main issue is about the backward compatibility.

New versions of openfst may change some API, which causes compile-time errors in Kaldi, like the one you mentioned in this issue.

[matthiasdotsh]

Let me rephrase my question:

There are currently two ways to compile Kaldi:

From https://github.com/kaldi-asr/kaldi/blob/master/INSTALL

Option 1 (bash + makefile):

Steps:
(1)
go to tools/ and follow INSTALL instructions there.

(2)
go to src/ and follow INSTALL instructions there.

Option 2 (cmake):

Go to cmake/ and follow INSTALL.md instructions there.
Note, it may not be well tested and some features are missing currently.

In your first reply, you mentioned this PR that supports using newer OpenFST versions from upstream.

The usage from the PR is:

make clean && make -j 18 OPENFST_VERSION=1.8.3

However, since https://github.com/kaldi-asr/kaldi/blob/master/cmake/third_party/openfst.cmake still refers to the kkm000/openfst fork and the upstream tarball does not contain a CMakeLists.txt, I think using an OpenFST version from openfst.org is only possible with Install Option 1 (bash + Makefile), not with Option 2 (cmake).

Is that correct?

[vcunat]

@csukuangfj: this patch does not change the API. It just helps the compiler to figure out typing for the ternary operator. While I'm not a C++ expert really (just C), I see no reason whatsoever for anything like #ifdef in this case.

EDIT: maybe you were talking about using a different openfst version with kaldi instead? In that case I'd understand talking about API changes and #ifdef, but that's not what this patch is about.