Fix 500s on `/state`, `/state_ids` when state not known (#2672)

This was due to bad error bubbling.

2 files changed, 12 insertions, 0 deletions

diff --git a/federationapi/routing/join.go b/federationapi/routing/join.go
index b48eaf78..1a121987 100644
--- a/federationapi/routing/join.go
+++ b/federationapi/routing/join.go
@@ -329,6 +329,12 @@ func SendJoin(
 			JSON: jsonerror.NotFound("Room does not exist"),
 		}
 	}
+	if !stateAndAuthChainResponse.StateKnown {
+		return util.JSONResponse{
+			Code: http.StatusForbidden,
+			JSON: jsonerror.Forbidden("State not known"),
+		}
+	}
 
 	// Check if the user is already in the room. If they're already in then
 	// there isn't much point in sending another join event into the room.
diff --git a/federationapi/routing/state.go b/federationapi/routing/state.go
index 6fdce20c..5377eb88 100644
--- a/federationapi/routing/state.go
+++ b/federationapi/routing/state.go
@@ -135,6 +135,12 @@ func getState(
 		return nil, nil, &resErr
 	}
 
+	if !response.StateKnown {
+		return nil, nil, &util.JSONResponse{
+			Code: http.StatusNotFound,
+			JSON: jsonerror.NotFound("State not known"),
+		}
+	}
 	if response.IsRejected {
 		return nil, nil, &util.JSONResponse{
 			Code: http.StatusNotFound,