8000 py/modsys.c: Add sys._exc_traceback. · micropython/micropython@d872e6e · GitHub
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DavidEGraysonDavidEGrayson
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py/modsys.c: Add sys._exc_traceback.
This makes it easier to provide custom formatting of exception stack traces, e.g. to make them fit on a tiny display. This is an experimental function that exposes internal details of MicroPython and it might change in the future. Signed-off-by: David (Pololu) <dev-david@pololu.com>
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‎docs/library/sys.rst

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@@ -52,6 +52,28 @@ Functions
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present in pre-built firmware (due to it affecting performance). The relevant
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configuration option is *MICROPY_PY_SYS_SETTRACE*.
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.. function:: _exc_traceback(exc)
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Retrieves traceback information from an exception object, including
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the filename, line number, and code block name for every code location
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on the call stack when the exception was thrown.
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.. admonition:: Difference to CPython
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:class: attention
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This function is a MicroPython extension intended to provide similar
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functionality to the ``__traceback__`` attribute of exception
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objects in CPython.
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.. admonition:: Unstable
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:class: attention
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This function directly exposes the internal traceback data used by
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MicroPython. Future versions might introduce incompatible changes to
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the format.
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Constants
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---------
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‎py/modsys.c

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@@ -150,6 +150,26 @@ STATIC mp_obj_t mp_sys_print_exception(size_t n_args, const mp_obj_t *args) {
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}
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MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_sys_print_exception_obj, 1, 2, mp_sys_print_exception);
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#if MICROPY_PY_SYS_EXC_TRACEBACK
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STATIC mp_obj_t mp_sys_exc_traceback(mp_obj_t exc) {
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if (!mp_obj_is_exception_instance(exc)) {
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mp_raise_TypeError(MP_ERROR_TEXT("not an exception"));
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}
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size_t n, *values;
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mp_obj_exception_get_traceback(exc, &n, &values);
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// Assumption: n is a multiple of 3.
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mp_obj_t obj = mp_obj_new_list(n, NULL);
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mp_obj_list_t *list = MP_OBJ_TO_PTR(obj);
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for (size_t i = 0; i < list->len; i += 3) {
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list->items[i + 0] = MP_OBJ_NEW_QSTR(values[i + 0]); // filename
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list->items[i + 1] = MP_OBJ_NEW_SMALL_INT(values[i + 1]); // line
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list->items[i + 2] = MP_OBJ_NEW_QSTR(values[i + 2]); // block
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}
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return obj;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_sys_exc_traceback_obj, mp_sys_exc_traceback);
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#endif
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#if MICROPY_PY_SYS_EXC_INFO
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STATIC mp_obj_t mp_sys_exc_info(void) {
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mp_obj_t cur_exc = MP_OBJ_FROM_PTR(MP_STATE_VM(cur_exception));
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*/
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{ MP_ROM_QSTR(MP_QSTR_print_exception), MP_ROM_PTR(&mp_sys_print_exception_obj) },
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#if MICROPY_PY_SYS_EXC_TRACEBACK
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{ MP_ROM_QSTR(MP_QSTR__exc_traceback), MP_ROM_PTR(&mp_sys_exc_traceback_obj) },
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#endif
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#if MICROPY_PY_SYS_ATEXIT
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{ MP_ROM_QSTR(MP_QSTR_atexit), MP_ROM_PTR(&mp_sys_atexit_obj) },
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#endif

‎py/mpconfig.h

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@@ -1386,6 +1386,11 @@ typedef double mp_float_t;
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#define MICROPY_PY_SYS_MODULES (1)
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#endif
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// Whether to provide "sys._exc_traceback" function.
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#ifndef MICROPY_PY_SYS_EXC_TRACEBACK
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#define MICROPY_PY_SYS_EXC_TRACEBACK (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_EXTRA_FEATURES)
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#endif
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// Whether to provide "sys.exc_info" function
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// Avoid enabling this, this function is Python2 heritage
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#ifndef MICROPY_PY_SYS_EXC_INFO

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