How to catch a usefull error message ?
Vincent Vande Vyvre
vincent.vande.vyvre at telenet.be
Tue Apr 23 15:21:52 EDT 2019
Le 23/04/19 à 20:54, Chris Angelico a écrit :
> On Wed, Apr 24, 2019 at 4:47 AM Vincent Vande Vyvre
> <vincent.vande.vyvre at telenet.be> wrote:
>
> Into the lib:
>
> static int
> ImgProc_init(ImgProc *self, PyObject *args, PyObject *kwds)
> {
> PyObject *tmp;
> char *fname;
>
> if (!PyArg_ParseTuple(args, "s", &fname))
> return NULL;
>
> tmp = self->src;
> self->src = PyUnicode_FromString(fname);
> Py_XDECREF(tmp);
> return 0;
> }
>
> If i do:
> try:
> tif = ImgProc(123)
> except Exception as why:
> print(sys.exc_info())
> raise
> I get:
> (<class 'SystemError'>, SystemError("<class '_liboqapy.ImgProc'>
> returned a result with an error set",), <traceback object at
> 0x7f3bcac748c8>)
> TypeError: argument 1 must be str, not int
>
> The above exception was the direct cause of the following exception:
>
> Traceback (most recent call last):
> File "/home/vincent/oqapy-3/trunk/filters/ui_lenscorrection.py", line
> 104, in on_main_cursor_changed
> self.prepare_preview_process()
> File "/home/vincent/oqapy-3/trunk/filters/ui_lenscorrection.py", line
> 137, in prepare_preview_process
> self.main.process_on_preview(params)
> File "/home/vincent/oqapy-3/trunk/filters/lenscorrection.py", line
> 56, in process_on_preview
> tif = ImgProc(123)
> SystemError: <class '_liboqapy.ImgProc'> returned a result with an error set
> --------------------------------------------------------------------------------
> Why a SystemError ?
> The SystemError means that you're using the Python C API in a way that
> doesn't make sense to the interpreter. You're leaving a marker saying
> "hey, I need you to throw an exception" but then you're also returning
> a value. You'll need to figure out where that's happening and exactly
> what is being called. How are you setting up your class?
>
> ChrisA
The syntaxe
if (!PyArg_ParseTuple(args, "s", &fname))
return NULL;
Is the usage described in the doc [*]
And without block try-except I get the good one error.
[*]
https://docs.python.org/3.5//extending/extending.html#back-to-the-example
Vincent
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