Build fail on macOS from `emitnative.c`

[bwhitman]

CircuitPython version and board name

main branch

Code/REPL

No code

Behavior

(circuitpython) outside/circuitpython - (main) > gmake -C mpy-cross

gmake: Entering directory '/Users/bwhitman/outside/circuitpython/mpy-cross'
- Verbosity options: any combination of "steps commands rules", as `make V=...` or env var BUILD_VERBOSE
In file included from ../py/emitnx64.c:16:
../py/emitnative.c:2423:5: error: variable length array folded to constant array as an extension [-Werror,-Wgnu-folding-constant]
 2423 |     MP_STATIC_ASSERT(MP_OBJ_STOP_ITERATION == 0);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../py/misc.h:57:51: note: expanded from macro 'MP_STATIC_ASSERT'
   57 | #define MP_STATIC_ASSERT(cond) ((void)sizeof(char[1 - 2 * !(cond)]))
      |                                                   ^~~~~~~~~~~~~~~
1 error generated.
-e See https://learn.adafruit.com/building-circuitpython; Adafruit Discord #circuitpython-dev
gmake: *** [../py/mkrules.mk:104: build/py/emitnx64.o] Error 1

Description

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Additional information

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[dhalbert]

Which version of arm-none-eabi-gcc are you using? See https://learn.adafruit.com/building-circuitpython/linux#cortex-m-builds-3049646

[bwhitman]

14.3.rel1

outside/circuitpython - (main) > which arm-none-eabi-gcc
/Users/bwhitman/Downloads/arm-gnu-toolchain-14.3.rel1-darwin-arm64-arm-none-eabi/bin/arm-none-eabi-gcc
outside/circuitpython - (main) > gmake -C mpy-cross     
gmake: Entering directory '/Users/bwhitman/outside/circuitpython/mpy-cross'
- Verbosity options: any combination of "steps commands rules", as `make V=...` or env var BUILD_VERBOSE
In file included from ../py/emitnx64.c:16:
../py/emitnative.c:2423:5: error: variable length array folded to constant array as an extension [-Werror,-Wgnu-folding-constant]
 2423 |     MP_STATIC_ASSERT(MP_OBJ_STOP_ITERATION == 0);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../py/misc.h:57:51: note: expanded from macro 'MP_STATIC_ASSERT'
   57 | #define MP_STATIC_ASSERT(cond) ((void)sizeof(char[1 - 2 * !(cond)]))
      |                                                   ^~~~~~~~~~~~~~~
1 error generated.
-e See https://learn.adafruit.com/building-circuitpython; Adafruit Discord #circuitpython-dev
gmake: *** [../py/mkrules.mk:104: build/py/emitnx64.o] Error 1
gmake: Leaving directory '/Users/bwhitman/outside/circuitpython/mpy-cross'

[dhalbert]

Sorry, since you are building mpy-cross, the version of arm-none-eabi-gcc is irrelevant here. It's the version of regular gcc that is important. What is gcc --version?

[bwhitman]

(circuitpython) outside/circuitpython - (main) > gcc --version
Apple clang version 17.0.0 (clang-1700.3.19.1)
Target: arm64-apple-darwin24.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

[dhalbert]

This was recently discovered and fixed in MicroPython: micropython#18116 and micropython#18145. We can pull this change in.

Same thing is being disccussed in discord: https://discord.com/channels/327254708534116352/327298996332658690/1424516202352611530 and following.