From 5223070c47c6fc35ee000b2392ae76d9fab54f16 Mon Sep 17 00:00:00 2001
From: Wenchao Xia <wenchaoqemu@gmail.com>
Date: Tue, 4 Mar 2014 18:44:39 -0800
Subject: qapi script: do not allow string discriminator

Since enum based discriminators provide better type-safety and
ensure that future qapi additions do not forget to adjust dependent
unions, forbid using string as discriminator from now on.

Signed-off-by: Wenchao Xia <wenchaoqemu@gmail.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
---
 scripts/qapi.py | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'scripts')

diff --git a/scripts/qapi.py b/scripts/qapi.py
index 2b43ad2f1b..bd00d01c0f 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -239,6 +239,11 @@ def check_union(expr, expr_info):
                                 "type '%s'"
                                 % (discriminator, base))
         enum_define = find_enum(discriminator_type)
+        # Do not allow string discriminator
+        if not enum_define:
+            raise QAPIExprError(expr_info,
+                                "Discriminator '%s' must be of enumeration "
+                                "type" % discriminator)
 
     # Check every branch
     for (key, value) in members.items():
-- 
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