fixes a bug

Author: rishabhpoddar

supertokens/supertokens.go

@@ -243,13 +243,19 @@ func (s *superTokens) middleware(theirHandler http.Handler) http.Handler {
 
 			LogDebugMessage("middleware: Request being handled by recipe. ID is: " + *id)
 
-			var tenantId, err = GetTenantIdFuncFromUsingMultitenancyRecipe(*finalTenantId, userContext)
-			if err != nil {
-				err = s.errorHandler(err, r, dw, userContext)
-				if err != nil && !dw.IsDone() {
-					s.OnSuperTokensAPIError(err, r, dw)
+			tenantId := "public"
+
+			if GetTenantIdFuncFromUsingMultitenancyRecipe != nil {
+				// this can be nil if the user has not used the multitenancy recipe
+				// which happens if they are only using the session recipe.
+				tenantId, err = GetTenantIdFuncFromUsingMultitenancyRecipe(*finalTenantId, userContext)
+				if err != nil {
+					err = s.errorHandler(err, r, dw, userContext)
+					if err != nil && !dw.IsDone() {
+						s.OnSuperTokensAPIError(err, r, dw)
+					}
+					return
 				}
-				return
 			}
 
 			apiErr := finalMatchedRecipe.HandleAPIRequest(*id, tenantId, r, dw, theirHandler.ServeHTTP, path, method, userContext)