[Buildroot] [PATCH v2 2/2] package/gnuradio: fix gnuradio python libraries for cross-compile

[Arnout Vandecappelle]

On 26/06/2023 09:05, Gwenhael Goavec-Merou wrote:
> From: Gwenhael Goavec-Merou <gwenhael.goavec-merou at trabucayre.com>
> 
> By default, module libraries have a suffix based on cpython version + host
> architecture: this is fine for a native compile when these libraries are used on

  I think that this is solved in the python infrastructure by setting

_PYTHON_HOST_PLATFORM="$(PKG_PYTHON_HOST_PLATFORM)"

Or it may be some other environment variable that is set. For sure though, the 
same problem would exist in normal python packages, and it is resolved there. So 
ideally we should use the same solution for gnuradio.

  Regards,
  Arnout

> the same computer (or similar computers). But when target architecture is not
> the same python is unable to find libraries due to the wrong suffix and produces
> unclear errors messages:
> 
> # python3
> Python 3.11.3 (main, Jun 19 2023, 14:15:44) [GCC 11.4.0] on linux
> Type "help", "copyright", "credits" or "license" for more information.
>>>> from gnuradio import blocks
> Traceback (most recent call last):
>    File "/home/xxx/buildroot/output/build/gnuradio-3.10.4.0/gr-blocks/python/blocks/__init__.py", line 18, in <module>
> ModuleNotFoundError: No module named 'gnuradio.blocks.blocks_python'
> 
> During handling of the above exception, another exception occurred:
> 
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
>    File "/home/xxx/buildroot/output/build/gnuradio-3.10.4.0/gr-blocks/python/blocks/__init__.py", line 22, in <module>
> ModuleNotFoundError: No module named 'gnuradio.blocks.blocks_python'
>>>>
> 
> By adding -DPYTHON_MODULE_EXTENSION=".so" at configure time, pybind11 will use
> this option instead of using host-python to forge suffix.
> 
> Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou at trabucayre.com>
> ---
> Changes v1 -> v2:
> - replaces patch by PYTHON_MODULE_EXTENSION option (result is the same
>    but less "noisy")
> ---
>   package/gnuradio/gnuradio.mk | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/package/gnuradio/gnuradio.mk b/package/gnuradio/gnuradio.mk
> index 1453b78493..d7b3b86c31 100644
> --- a/package/gnuradio/gnuradio.mk
> +++ b/package/gnuradio/gnuradio.mk
> @@ -119,6 +119,8 @@ GNURADIO_CONF_OPTS += -DENABLE_PYTHON=ON
>   # mandatory to avoid pybind11 to overwrite variables provided
>   # by gnuradio and buildroot
>   GNURADIO_CONF_OPTS += -DPYBIND11_PYTHONLIBS_OVERWRITE=OFF
> +# force libraries suffix (avoid to have libxxx.PYTHONVER-HOST_ARCH.so)
> +GNURADIO_CONF_OPTS += -DPYTHON_MODULE_EXTENSION=".so"
>   # mandatory to install python modules in site-packages and to use
>   # correct path for python libraries
>   GNURADIO_CONF_OPTS += -DGR_PYTHON_RELATIVE=ON \