add assert message for errorhandler exception type

2020-04-16 17:01:51 +01:00 · 2020-04-16 17:01:51 +01:00 · 148c89bccd
commit 148c89bccd
parent 64790568ed
2 changed files with 11 additions and 1 deletions
--- a/src/flask/app.py
+++ b/src/flask/app.py
@ -1270,7 +1270,9 @@ class Flask(_PackageBoundObject):
        else:
            exc_class = exc_class_or_code

-        assert issubclass(exc_class, Exception)
+        assert issubclass(
+            exc_class, Exception
+        ), "Custom exceptions must be subclasses of Exception."

        if issubclass(exc_class, HTTPException):
            return exc_class, exc_class.code