Merge pull request #12353 from mattip/check-threshold

BUG: test, fix for threshold='nan'

2 files changed, 10 insertions, 1 deletions

diff --git a/numpy/core/arrayprint.py b/numpy/core/arrayprint.py
index 075d75340..6a71de226 100644
--- a/numpy/core/arrayprint.py
+++ b/numpy/core/arrayprint.py
@@ -26,6 +26,7 @@ __docformat__ = 'restructuredtext'
 
 import sys
 import functools
+import numbers
 if sys.version_info[0] >= 3:
     try:
         from _thread import get_ident
@@ -86,7 +87,11 @@ def _make_options_dict(precision=None, threshold=None, edgeitems=None,
     if legacy not in [None, False, '1.13']:
         warnings.warn("legacy printing option can currently only be '1.13' or "
                       "`False`", stacklevel=3)
-
+    if threshold is not None:
+        # forbid the bad threshold arg suggested by stack overflow, gh-12351
+        if not isinstance(threshold, numbers.Number) or np.isnan(threshold):
+            raise ValueError("threshold must be numeric and non-NAN, try "
+                             "sys.maxsize for untruncated representation")
     return options
 
 
diff --git a/numpy/core/tests/test_arrayprint.py b/numpy/core/tests/test_arrayprint.py
index 6522c6e8a..7a858d2e2 100644
--- a/numpy/core/tests/test_arrayprint.py
+++ b/numpy/core/tests/test_arrayprint.py
@@ -842,6 +842,10 @@ class TestPrintOptions(object):
                     [[ 0.]]]])""")
         )
 
+    def test_bad_args(self):
+        assert_raises(ValueError, np.set_printoptions, threshold='nan')
+        assert_raises(ValueError, np.set_printoptions, threshold=u'1')
+        assert_raises(ValueError, np.set_printoptions, threshold=b'1')
 
 def test_unicode_object_array():
     import sys