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BUG: Fix dot and inner type/value exception failures #6988

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Merged
merged 3 commits into from
Jan 12, 2016
Merged

BUG: Fix dot and inner type/value exception failures #6988

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b491cc8
TST: Ensure `dot` fails correctly if array types cannot be coerced in…
jakirkham Jan 9, 2016
67592d3
TST: Ensure `inner` fails correctly if array types cannot be coerced …
jakirkham Jan 9, 2016
bab118d
BUG: Clear error before constructing error message using calls to `Py…
jakirkham Jan 10, 2016
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28 changes: 24 additions & 4 deletions numpy/core/src/multiarray/ctors.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1926,14 +1926,34 @@ PyArray_FromArray(PyArrayObject *arr, PyArray_Descr *newtype, int flags)
/* Raise an error if the casting rule isn't followed */
if (!PyArray_CanCastArrayTo(arr, newtype, casting)) {
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After some more debugging with gdb apparently the segmentation fault is occurring at this line. The real line responsible is in PyArray_EquivTypes. Somehow PyArray_EquivTypes is getting NULL for its first type, which is the cause of the problem.

PyObject *errmsg;
PyArray_Descr *arr_descr = NULL;
PyObject *arr_descr_repr = NULL;
PyObject *newtype_repr = NULL;

PyErr_Clear();
errmsg = PyUString_FromString("Cannot cast array data from ");
PyUString_ConcatAndDel(&errmsg,
PyObject_Repr((PyObject *)PyArray_DESCR(arr)));
arr_descr = PyArray_DESCR(arr);
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I think calling Py_DECREF(arr_descr); may have been the cause of the segmentation faults. At the time, I didn't realize PyArray_DESCR returned a borrowed reference. So, I was effectively deleting part of the array, but leaving the rest of the array around. As a result, we saw some weird behavior due to this.

if (arr_descr == NULL) {
Py_DECREF(newtype);
Py_DECREF(errmsg);
return NULL;
}
arr_descr_repr = PyObject_Repr((PyObject *)arr_descr);
if (arr_descr_repr == NULL) {
Py_DECREF(newtype);
Py_DECREF(errmsg);
return NULL;
}
PyUString_ConcatAndDel(&errmsg, arr_descr_repr);
PyUString_ConcatAndDel(&errmsg,
PyUString_FromString(" to "));
PyUString_ConcatAndDel(&errmsg,
PyObject_Repr((PyObject *)newtype));
newtype_repr = PyObject_Repr((PyObject *)newtype);
if (newtype_repr == NULL) {
Py_DECREF(newtype);
Py_DECREF(errmsg);
return NULL;
}
PyUString_ConcatAndDel(&errmsg, newtype_repr);
PyUString_ConcatAndDel(&errmsg,
PyUString_FromFormat(" according to the rule %s",
npy_casting_to_string(casting)));
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14 changes: 14 additions & 0 deletions numpy/core/tests/test_multiarray.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2041,6 +2041,13 @@ def __numpy_ufunc__(self, ufunc, method, pos, inputs, **kwargs):
assert_raises(TypeError, np.dot, b, c)
assert_raises(TypeError, c.dot, b)

def test_dot_type_mismatch(self):
c = 1.
A = np.array((1,1), dtype='i,i')

assert_raises(ValueError, np.dot, c, A)
assert_raises(TypeError, np.dot, A, c)
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So, I managed to get this built so I can debug with python3-dbg interactively and discovered this line will cause the strange exception. However, the line before does not cause the exception.


def test_diagonal(self):
a = np.arange(12).reshape((3, 4))
assert_equal(a.diagonal(), [0, 5, 10])
Expand Down Expand Up @@ -4825,6 +4832,13 @@ def test_matmul_inplace():

class TestInner(TestCase):

def test_inner_type_mismatch(self):
c = 1.
A = np.array((1,1), dtype='i,i')

assert_raises(TypeError, np.inner, c, A)
assert_raises(TypeError, np.inner, A, c)
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Same story as above. This line will cause the exception, as well.

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Just to add that this error occurs with python 3.5 debug also.


def test_inner_scalar_and_vector(self):
for dt in np.typecodes['AllInteger'] + np.typecodes['AllFloat'] + '?':
sca = np.array(3, dtype=dt)[()]
Expand Down