add type check to product upc search filter

rattail/pyramid/views/products.py

@@ -88,9 +88,30 @@ class ProductsGrid(SearchableAlchemyGridView):
             }
 
     def filter_map(self):
+
+        def filter_upc():
+
+            def filter_is(q, v):
+                try:
+                    v = int(v)
+                except ValueError:
+                    return q
+                else:
+                    return q.filter(field == v) if v else q
+
+            def filter_not(q, v):
+                try:
+                    v = int(v)
+                except ValueError:
+                    return q
+                else:
+                    return q.filter(field != v) if v else q
+
+            return {'is': filter_is, 'nt': filter_not}
+
         return self.make_filter_map(
-            exact=['upc'],
             ilike=['description', 'size'],
+            upc=filter_upc(),
             brand=self.filter_ilike(rattail.Brand.name),
             department=self.filter_ilike(rattail.Department.name),
             subdepartment=self.filter_ilike(rattail.Subdepartment.name),