BUG: Prevent unsafe string concatenation

This did not handle exceptions correctly.
Changed to use python to format the exception like all the others in this file.

This also adds quotes around the ufunc name.

1 files changed, 16 insertions, 0 deletions

diff --git a/numpy/core/_exceptions.py b/numpy/core/_exceptions.py
index 1dcea6255..a1af7a78d 100644
--- a/numpy/core/_exceptions.py
+++ b/numpy/core/_exceptions.py
@@ -37,6 +37,22 @@ class UFuncTypeError(TypeError):
 
 
 @_display_as_base
+class _UFuncBinaryResolutionError(UFuncTypeError):
+    """ Thrown when a binary resolution fails """
+    def __init__(self, ufunc, dtypes):
+        super().__init__(ufunc)
+        self.dtypes = tuple(dtypes)
+        assert len(self.dtypes) == 2
+
+    def __str__(self):
+        return (
+            "ufunc {!r} cannot use operands with types {!r} and {!r}"
+        ).format(
+            self.ufunc.__name__, *self.dtypes
+        )
+
+
+@_display_as_base
 class _UFuncNoLoopError(UFuncTypeError):
     """ Thrown when a ufunc loop cannot be found """
     def __init__(self, ufunc, dtypes):