DEP: Stricter arg checking for array ordering

The bug traces to the PyArray_OrderConverter
method in conversion_utils.c, where no errors
are thrown if the ORDER parameter passed in
is not of the string data-type or has a string
value of length greater than one. This commit
causes a DeprecationWarning to be raised, which
will later be turned into a TypeError or another
type of error in a future release.

Closes gh-6598.

2 files changed, 51 insertions, 0 deletions

diff --git a/numpy/core/src/multiarray/conversion_utils.c b/numpy/core/src/multiarray/conversion_utils.c
index 88064c1d6..d7a617875 100644
--- a/numpy/core/src/multiarray/conversion_utils.c
+++ b/numpy/core/src/multiarray/conversion_utils.c
@@ -540,6 +540,15 @@ PyArray_OrderConverter(PyObject *object, NPY_ORDER *val)
         return ret;
     }
     else if (!PyBytes_Check(object) || PyBytes_GET_SIZE(object) < 1) {
+        /* 2015-12-14, 1.11 */
+        int ret = DEPRECATE("Non-string object detected for "
+                            "the array ordering. Please pass "
+                            "in 'C', 'F', 'A', or 'K' instead");
+
+        if (ret < 0) {
+            return -1;
+        }
+
         if (PyObject_IsTrue(object)) {
             *val = NPY_FORTRANORDER;
         }
@@ -553,6 +562,18 @@ PyArray_OrderConverter(PyObject *object, NPY_ORDER *val)
     }
     else {
         str = PyBytes_AS_STRING(object);
+        if (strlen(str) != 1) {
+            /* 2015-12-14, 1.11 */
+            int ret = DEPRECATE("Non length-one string passed "
+                                "in for the array ordering. "
+                                "Please pass in 'C', 'F', 'A', "
+                                "or 'K' instead");
+
+            if (ret < 0) {
+                return -1;
+            }
+        }
+
         if (str[0] == 'C' || str[0] == 'c') {
             *val = NPY_CORDER;
         }
diff --git a/numpy/core/tests/test_deprecations.py b/numpy/core/tests/test_deprecations.py
index f6dc3d842..65ddc1e77 100644
--- a/numpy/core/tests/test_deprecations.py
+++ b/numpy/core/tests/test_deprecations.py
@@ -400,6 +400,36 @@ class TestNonCContiguousViewDeprecation(_DeprecationTestCase):
         self.assert_deprecated(np.ones((2,2)).T.view, args=(np.int8,))
 
 
+class TestInvalidOrderParameterInputForFlattenArrayDeprecation(_DeprecationTestCase):
+    """Invalid arguments to the ORDER parameter in array.flatten() should not be
+    allowed and should raise an error.  However, in the interests of not breaking
+    code that may inadvertently pass invalid arguments to this parameter, a
+    DeprecationWarning will be issued instead for the time being to give developers
+    time to refactor relevant code.
+    """
+
+    def test_flatten_array_non_string_arg(self):
+        x = np.zeros((3, 5))
+        self.message = ("Non-string object detected for "
+                        "the array ordering. Please pass "
+                        "in 'C', 'F', 'A', or 'K' instead")
+        self.assert_deprecated(x.flatten, args=(np.pi,))
+
+    def test_flatten_array_invalid_string_arg(self):
+        # Tests that a DeprecationWarning is raised
+        # when a string of length greater than one
+        # starting with "C", "F", "A", or "K" (case-
+        # and unicode-insensitive) is passed in for
+        # the ORDER parameter. Otherwise, a TypeError
+        # will be raised!
+
+        x = np.zeros((3, 5))
+        self.message = ("Non length-one string passed "
+                        "in for the array ordering. Please "
+                        "pass in 'C', 'F', 'A', or 'K' instead")
+        self.assert_deprecated(x.flatten, args=("FACK",))
+
+
 class TestTestDeprecated(object):
     def test_assert_deprecated(self):
         test_case_instance = _DeprecationTestCase()