QUERY · ISSUE

exception_chain.py.

openby agattiopened 2025-06-22updated 2025-12-23

bug

Port, board and/or hardware

Unix on Linux/amd64

MicroPython version

MicroPython v1.26.0-preview.261.gbcc8d4ee1.dirty on 2025-06-22; linux [GCC 15.1.1] version

Reproduction

Build mpy-cross with no special flags (make -C mpy-cross clean && make -C mpy-cross)
Compile tests/basics/exception_chain.py into native code (arch does not matter) with mpy-cross -X emit=native -march=debug tests/basics/exception_chain.py
mpy-cross will crash.

Expected behaviour

Compiling tests/basics/exception_chain.py should not crash mpy-cross.

Observed behaviour

mpy-cross crashes with:

mpy-cross: ../py/emitnative.c:2947: emit_native_raise_varargs: Assertion `n_args == 1' failed.`

Additional Information

If having a multi-arg exception is not supported for native code compilation, then an error message should be printed rather than crashing the compiler.

Code of Conduct

Yes, I agree

CANDIDATE · PULL REQUEST

mpy-cross: exit with error if arch not given when needed, and add `emit=host` option to help

mergedby dpgeorgeopened 2025-05-23updated 2025-06-04

py-core

Summary

This PR addresses two minor issues with mpy-cross:

mpy-cross will crash if called as mpy-cross -X emit=native foo.py, because it tries to use the native emitter with no target architecture set; fixed by checking that an architecture is set when -X emit=native or X emit=viper is used
document the availability of the -X emit=host option in the help

Testing

Tested by running mpy-cross -X emit=native, it now raises an exception.

Also ran mpy-cross -h to see the modified help message.