Do not set pattern on non-string values

Fixes #68

src/drf_yasg/generators.py

@@ -405,8 +405,8 @@ class OpenAPISchemaGenerator(object):
         for variable in uritemplate.variables(path):
             model, model_field = get_queryset_field(queryset, variable)
             attrs = get_basic_type_info(model_field) or {'type': openapi.TYPE_STRING}
-            if hasattr(view_cls, 'lookup_value_regex') and getattr(view_cls, 'lookup_field', None) == variable:
-                attrs['pattern'] = view_cls.lookup_value_regex
+            if getattr(view_cls, 'lookup_field', None) == variable and attrs['type'] == openapi.TYPE_STRING:
+                attrs['pattern'] = getattr(view_cls, 'lookup_value_regex', attrs.get('pattern', None))
 
             if model_field and model_field.help_text:
                 description = force_text(model_field.help_text)

src/drf_yasg/inspectors/field.py

@@ -361,7 +361,10 @@ def get_basic_type_info(field):
     else:  # pragma: no cover
         return None
 
-    pattern = find_regex(field) if format in (None, openapi.FORMAT_SLUG) else None
+    pattern = None
+    if swagger_type == openapi.TYPE_STRING and format in (None, openapi.FORMAT_SLUG):
+        pattern = find_regex(field)
+
     limits = find_limits(field)
 
     result = OrderedDict([

testproj/todo/views.py

@@ -8,6 +8,9 @@ class TodoViewSet(viewsets.ReadOnlyModelViewSet):
     queryset = Todo.objects.all()
     serializer_class = TodoSerializer
 
+    lookup_field = 'id'
+    lookup_value_regex = '[0-9]+'
+
 
 class TodoAnotherViewSet(viewsets.ReadOnlyModelViewSet):
     queryset = TodoAnother.objects.all()