BUG: prevent crash when ufunc doc string is null

3 files changed, 14 insertions, 2 deletions

diff --git a/numpy/core/src/umath/ufunc_object.c b/numpy/core/src/umath/ufunc_object.c
index 950914b4e..b871061b3 100644
--- a/numpy/core/src/umath/ufunc_object.c
+++ b/numpy/core/src/umath/ufunc_object.c
@@ -5596,8 +5596,10 @@ ufunc_get_doc(PyUFuncObject *ufunc)
     if (doc == NULL) {
         return NULL;
     }
-    PyUString_ConcatAndDel(&doc,
-        PyUString_FromFormat("\n\n%s", ufunc->doc));
+    if (ufunc->doc != NULL) {
+        PyUString_ConcatAndDel(&doc,
+            PyUString_FromFormat("\n\n%s", ufunc->doc));
+    }
     return doc;
 }
 
diff --git a/numpy/core/src/umath/umath_tests.c.src b/numpy/core/src/umath/umath_tests.c.src
index 6cd181897..8d9009a1a 100644
--- a/numpy/core/src/umath/umath_tests.c.src
+++ b/numpy/core/src/umath/umath_tests.c.src
@@ -305,6 +305,12 @@ addUfuncs(PyObject *dictionary) {
                     0, euclidean_pdist_signature);
     PyDict_SetItemString(dictionary, "euclidean_pdist", f);
     Py_DECREF(f);
+    f = PyUFunc_FromFuncAndDataAndSignature(inner1d_functions, inner1d_data,
+                    inner1d_signatures, 2, 2, 1, PyUFunc_None, "inner1d_no_doc",
+                    NULL,
+                    0, inner1d_signature);
+    PyDict_SetItemString(dictionary, "inner1d_no_doc", f);
+    Py_DECREF(f);
 }
 
 
diff --git a/numpy/core/tests/test_ufunc.py b/numpy/core/tests/test_ufunc.py
index 3d6251253..547cc495b 100644
--- a/numpy/core/tests/test_ufunc.py
+++ b/numpy/core/tests/test_ufunc.py
@@ -1283,6 +1283,10 @@ class TestUfunc(TestCase):
         assert_equal(y_base[1,:], y_base_copy[1,:])
         assert_equal(y_base[3,:], y_base_copy[3,:])
 
+    def test_no_doc_string(self):
+        # gh-9337
+        assert_('\n' not in umt.inner1d_no_doc.__doc__)
+
 
 if __name__ == "__main__":
     run_module_suite()