convert HTTPException.description to string

CHANGES.rst

@@ -16,6 +16,8 @@ Unreleased
     characters. :issue:`2125`
 -   Type checking understands that calling ``headers.get`` with a string
     default will always return a string. :issue:`2128`
+-   If ``HTTPException.description`` is not a string,
+    ``get_description`` will convert it to a string. :issue:`2115`
 
 
 Version 2.0.0

src/werkzeug/exceptions.py

@@ -156,7 +156,14 @@ def get_description(
         scope: t.Optional[dict] = None,
     ) -> str:
         """Get the description."""
-        description = escape(self.description).replace("\n", "<br>")  # type: ignore
+        if self.description is None:
+            description = ""
+        elif not isinstance(self.description, str):
+            description = str(self.description)
+        else:
+            description = self.description
+
+        description = escape(description).replace("\n", "<br>")
         return f"<p>{description}</p>"
 
     def get_body(

tests/test_exceptions.py

@@ -142,3 +142,7 @@ class TestResponse(Response):
     exc = cls(response=TestResponse())
     rp = exc.get_response({})
     assert isinstance(rp, TestResponse)
+
+
+def test_description_none():
+    HTTPException().get_response()