← index #18105Issue #18172
Off-topic · high · value 0.869
QUERY · ISSUE

uctypes incompatibility with OBJ_REPR_B

openby jepleropened 2025-09-20updated 2025-09-20
bug

Port, board and/or hardware

unix, 32-bit, obj_repr_b

MicroPython version

based on v1.27.0-preview-154-g44986b1f04

Reproduction

  1. Make a build with OBJ_REPR_B
  2. Look at the uctypes constants

Expected behaviour

All the constants are distinct

Observed behaviour

Some of the constants are duplicates

>>> import uctypes
>>> assert uctypes.INT8 != uctypes.BFINT8
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AssertionError: 

Additional Information

See more discussion at https://github.com/micropython/micropython/pull/17688#discussion_r2357500386

Patch to add a REPR_B coverage build to ci.sh:


diff --git a/tools/ci.sh b/tools/ci.sh
index 901059991e..5afe089ccb 100755
--- a/tools/ci.sh
+++ b/tools/ci.sh
@@ -543,6 +543,14 @@ CI_UNIX_OPTS_SANITIZE_UNDEFINED=(
     LDFLAGS_EXTRA="-fsanitize=undefined -fno-sanitize=nonnull-attribute"
 )
 
+CI_UNIX_OPTS_REPR_B=(
+    VARIANT=coverage
+    CFLAGS_EXTRA="-DMICROPY_OBJ_REPR=MICROPY_OBJ_REPR_B -Dmp_int_t=int32_t -Dmp_uint_t=uint32_t"
+    MICROPY_FORCE_32BIT=1
+    RUN_TESTS_MPY_CROSS_FLAGS="--mpy-cross-flags=\"-march=x86 -msmall-int-bits=30\""
+
+)
+
 function ci_unix_build_helper {
     make ${MAKEOPTS} -C mpy-cross
     make ${MAKEOPTS} -C ports/unix "$@" submodules
@@ -688,6 +696,15 @@ function ci_unix_32bit_setup {
     python3 --version
 }
 
+function ci_unix_coverage_repr_b_build {
+    ci_unix_build_helper "${CI_UNIX_OPTS_REPR_B[@]}"
+    ci_unix_build_ffi_lib_helper gcc -m32
+}
+
+function ci_unix_coverage_repr_b_run_tests {
+    ci_unix_run_tests_helper "${CI_UNIX_OPTS_REPR_B[@]}"
+}
+
 function ci_unix_coverage_32bit_build {
     ci_unix_build_helper VARIANT=coverage MICROPY_FORCE_32BIT=1
     ci_unix_build_ffi_lib_helper gcc -m32
-- 
2.47.3

Code of Conduct

Yes, I agree

CANDIDATE · ISSUE

bytearray(uctypes.bytes_at(0, 8)) segfaults in memcpy

openby MaksimFengopened 2025-09-29updated 2026-03-20
bugproposed-close

Port, board and/or hardware

Unix port

MicroPython version

MicroPython v1.27.0-preview.107.gd1607598f on 2025-09-09; linux [GCC 14.2.0] version

Reproduction

import uctypes
arr = uctypes.bytes_at(0, 8)
arr2 = bytearray(arr)
arr2[0] = 1

Expected behaviour

A Python-level exception when the source buffer refers to an unreadable address (e.g., ValueError or OSError), or the unix port rejects bytes_at(0, 8) up front.

Observed behaviour

Program received signal SIGSEGV, Segmentation fault.
[#0] 0x7ffff7d95780 → __memcpy_avx_unaligned_erms()
[#1] 0x5555555fa3fd → memcpy(__dest=<optimised out>, __src=<optimised out>, __len=0x8)
[#2] 0x5555555fa3fd → array_construct(typecode=0x1, initializer=<optimised out>)
[#3] 0x5555555fa73b → bytearray_make_new(type_in=<optimised out>, n_args=0x1, n_kw=<optimised out>, args=0x7ffff7e27de0)
[#4] 0x555555618eff → type_call(self_in=<optimised out>, n_args=<optimised out>, n_kw=<optimised out>, args=<optimised out>)
[#5] 0x5555555ed738 → mp_call_function_n_kw(fun_in=0x55555571d070 <mp_type_bytearray>, n_args=0x1, n_kw=0x0, args=0x7ffff7e27de0)
[#6] 0x555555629936 → mp_execute_bytecode(code_state=0x7ffff7e27da0, inject_exc=<optimised out>)
[#7] 0x555555602482 → fun_bc_call(self_in=0x7ffff7e27ce0, n_args=<optimised out>, n_kw=<optimised out>, args=0x0)
[#8] 0x5555555ed738 → mp_call_function_n_kw(fun_in=0x7ffff7e27ce0, n_args=0x0, n_kw=0x0, args=0x0)
[#9] 0x5555555f0211 → mp_call_function_0(fun=<optimised out>)

Additional Information

No, I've provided everything above.

Code of Conduct

Yes, I agree

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