Unable to build mpy-cross with Apple clang version 17.0.0 #18116
Description
Port, board and/or hardware
any
MicroPython version
Tested on v1.26.0 and latest master today v1.26.0-161-g8757eb715.
Reproduction
cd mpy-cross
make
Expected behaviour
Expected to build mpy-cross, like
...
LINK build/mpy-cross
__TEXT __DATA __OBJC others dec hex
425984 16384 0 4295032832 4295475200 10007c000
Observed behaviour
Build fails with :
CC ../py/parse.c
../py/parse.c:349:19: error: variable length array folded to constant array as an extension [-Werror,-Wgnu-folding-constant]
349 | || mp_obj_is_float(*o)
| ^~~~~~~~~~~~~~~~~~~
../py/obj.h:120:28: note: expanded from macro 'mp_obj_is_float'
120 | #define mp_obj_is_float(o) mp_obj_is_type((o), &mp_type_float)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../py/obj.h:979:31: note: expanded from macro 'mp_obj_is_type'
979 | #define mp_obj_is_type(o, t) (mp_type_assert_not_bool_int_str_nonetype(t) && mp_obj_is_exact_type(o, t))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../py/obj.h:973:5: note: expanded from macro 'mp_type_assert_not_bool_int_str_nonetype'
973 | MP_STATIC_ASSERT_NONCONSTEXPR((t) != &mp_type_bool), assert((t) != &mp_type_bool), \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../py/misc.h:76:45: note: expanded from macro 'MP_STATIC_ASSERT_NONCONSTEXPR'
76 | #define MP_STATIC_ASSERT_NONCONSTEXPR(cond) MP_STATIC_ASSERT(cond)
| ^~~~~~~~~~~~~~~~~~~~~~
../py/misc.h:66:51: note: expanded from macro 'MP_STATIC_ASSERT'
66 | #define MP_STATIC_ASSERT(cond) ((void)sizeof(char[1 - 2 * !(cond)]))
| ^~~~~~~~~~~~~~~
... same error repeated ...
12 errors generated.
-e See https://github.com/micropython/micropython/wiki/Build-Troubleshooting
make: *** [build/py/parse.o] Error 1
Additional Information
I was able to build may-cross before.
This fails after upgrading to macos 26, that probably upgraded clang to version 17.0.0 in the process.
This clang version seems to dislike the MP_STATIC_ASSERT macro.
Compilation works when silencing the gnu-folding-constant warning/error :
like (in micropython/py/misc.h) :
// Static assertion macro
#define MP_STATIC_ASSERT(cond) \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wgnu-folding-constant\"") \
((void)sizeof(char[1 - 2 * !(cond)])) \
_Pragma("GCC diagnostic pop")... but I don't know if its safe to do, and how it'll affect other compilers.
Code of Conduct
Yes, I agree