Re: conda build fails with: ImportError: generic_type: type "square_ff" referenced unknown base type "gr::block"

[Ryan Volz]

Hi Franco,

Thanks for trying this out! The more people that use it, the better we can make 
it work.

What you've run into is indeed a pybind11 incompatibility. It's happening not because the 
pybind11 version has changed between building GNU Radio and the OOT, but because the 
version of GCC has changed between the two builds. Conda-forge has recently migrated from 
GCC 9 to 10, the existing `gnuradio` packages were built with GCC 9, and your fresh OOT 
build from a recipe is using GCC 10. It works the "normal" way without a recipe 
because `gnuradio-build-deps` installs GCC 9.

I was hoping that no one would run into this until the next releases of GNU 
Radio, at which time I could upgrade to GCC 10 and not break existing OOT 
packages built with GCC 9. As a temporary fix until that time, you can add the 
following lines to a `conda_build_config.yaml` file in the same directory as 
`meta.yaml` in your OOT recipe:

c_compiler_version:
  - 9  # [linux]
cxx_compiler_version:
  - 9  # [linux]

That will override conda-forge's global compiler settings and use GCC 9, which 
will give you compatible Python bindings.

Cheers,
Ryan

P.S.

As it so happens, I have just started playing around with adding a conda recipe 
to the gr-newmod OOT template created by gr_modtool:

https://github.com/ryanvolz/gnuradio/tree/05568f8f2937f9fc613cc9d518a771dd0f06a5ae/gr-utils/modtool/templates/gr-newmod/.conda

You could copy that whole .conda directory into a module's source tree, modify 
the .conda/recipe/meta.yaml, and get results very similar to what you've shared 
at the Google drive link. Of course, this still also needs the GCC version fix 
described above!

On 3/22/22 9:52 PM, Franco VENTURI wrote:
> In order to learn how conda recipes and conda build work, I did the following 
> steps on my computer:
>
> - created a VM running the latest version of Ubuntu (21.10); I did all the 
> remaining steps inside this VM
> - installed conda (miniforge3), created the 'gnuradio' environment, installed the 
> latest version of gnuradio from conda (3.10.1.1), ran 'conda upgrade -all', ran a 
> quick check with 'gnuradio-compantion' - for this part I followed the instructions in 
> the GNU Radio Wiki (https://wiki.gnuradio.org/index.php/CondaInstall 
> <https://wiki.gnuradio.org/index.php/CondaInstall>)
> - ran 'conda install gnuradio-build-deps' and 'conda activate $CONDA_DEFAULT_ENV' as 
> per the instructions here: 
> https://wiki.gnuradio.org/index.php/CondaInstall#Building_OOT_modules_to_use_with_conda-installed_GNU_Radio
>  
> <https://wiki.gnuradio.org/index.php/CondaInstall#Building_OOT_modules_to_use_with_conda-installed_GNU_Radio>
> - followed the GNU Radio OOT Modules tutorial 
> (https://wiki.gnuradio.org/index.php/OutOfTreeModules 
> <https://wiki.gnuradio.org/index.php/OutOfTreeModules>) to create the sample 
> 'gr-howto' OOT module with the two blocks 'square_ff' and 'square2_ff'
> - in the sample OOT howto module I ran the commands:
>      mkdir build
>      cd build
>      cmake -G Ninja -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX 
> -DCMAKE_PREFIX_PATH=$CONDA_PREFIX -DLIB_SUFFIX="" ..
>      cmake --build .
>      cmake --build . --target install
> and I was able to build the sample 'gr-howto' module, and ran the QA tests 
> without any errors
> - I then created a conda recipe following the steps in Ryan Volz template 
> (https://github.com/ryanvolz/gnuradio-oot-template-feedstock 
> <https://github.com/ryanvolz/gnuradio-oot-template-feedstock>); modified the 
> meta.yaml file, and the build.sh file (didn't touch bld.bat since my build/host 
> environment is Ubuntu)
> - I installed conda-build and ran the command 'conda build .' in the directory 
> with the recipe
> - After a few minutes the compile/link part ran without errors, however the QA 
> tests failed with the error message:
>
>      ImportError: generic_type: type "square_ff" referenced unknown base type 
> "gr::block"
>
> For those interested in seeing all the files (howto module, meta.yaml, 
> build.sh), I uploaded them to my Google drive and this is the link: 
> https://drive.google.com/file/d/1rkMcrsF9jLxUvgOU1F3kpbCRij4e9qa-/view?usp=sharing
>
> I know that error message is due to pybind11 and I saw it was mentioned in this mailing 
> list before (https://lists.gnu.org/archive/html/discuss-gnuradio/2021-05/msg00056.html 
> <https://lists.gnu.org/archive/html/discuss-gnuradio/2021-05/msg00056.html> and 
> https://github.com/gnuradio/gnuradio/issues/4841 
> <https://github.com/gnuradio/gnuradio/issues/4841>), but in this case the module does 
> work with the conda gnuradio environment if built the 'normal' way using the 'cmake' 
> commands above; it fails when run inside a 'conda build' recipe.
>
> Thanks in advance,
> Franco