How to embed Python interpreter?

[axbycc-mark]

Sorry I'm not so good at Bazel. The current doc says "embed Python, add @rules_python//python/cc:current_py_cc_libs as a dependency to your cc_binary."

But this doesn't seem enough because the header "pybind11/embed.h" would not be found. What additional dependencies should I add to build the following minimal example?

#include <pybind11/embed.h> // everything needed for embedding
namespace py = pybind11;

int main() {
    py::scoped_interpreter guard{}; // start the interpreter and keep it alive

    py::print("Hello, World!"); // use the Python API
}

[junyer]

For something like "hello, world" tinkering, it might be easiest to use the pybind_library_test() rule, which will provide the headers and the libraries (i.e. don't specify @rules_python//python/cc:current_py_cc_libs in deps) and will output a C++ binary. We only just got it working again about a month ago, mind you, so please let me know if you encounter any problems!

[axbycc-mark]

I tried this out and I'm getting a runtime exception on Windows 10. Step by step debugging in Visual Studio takes me down into pylifecycle.c from the Python source code, which was originally at C:\Users\runneradmin\AppData\Local\Temp\python-build-ppgzl_qt\Python-3.11.7\Python\pylifecycle.c on my machine. I'm guessing Bazel put it there when it built the default hermetic host python toolchain. Is there a way for Bazel to regenerate this file so that I can continue debugging?

[junyer]

Oh, whoa! Now I'm wondering whether such crashing might be related to "trying to take settings from the local environment" somehow? Apart from that, the hermetic Python toolchains are indygreg/python-build-standalone releases; Bazel doesn't build Python itself and so neither rules_python nor pybind11_bazel can do much to help here, AFAIK.

[axbycc-mark]

I've investigated this issue much more and I posted my findings under the issue you linked. The resolution must wait on some new code on the python_rules side. It is also blocked on a bug fix for bazelbuild/rules_python#1823 which is currently in progress.

[junyer]

Many thanks for digging into this! :D