[Qemu-devel] [PULL 01/15] qapi: Assert in places where variants are not handled

From: Markus Armbruster <armbru@redhat.com>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [PULL 01/15] qapi: Assert in places where variants are not handled
Date: Fri, 18 Mar 2016 11:04:15 +0100	[thread overview]
Message-ID: <1458295469-22215-2-git-send-email-armbru@redhat.com> (raw)
In-Reply-To: <1458295469-22215-1-git-send-email-armbru@redhat.com>

From: Eric Blake <eblake@redhat.com>

We are getting closer to the point where we could use one union
as the base or variant type within another union type (as long
as there are no collisions between any possible combination of
member names allowed across all discriminator choices).  But
until we get to that point, it is worth asserting that variants
are not present in places where we are not prepared to handle
them: when exploding a type into a parameter list, we do not
expect variants.  The qapi.py code is already checking this,
via the older check_type() method; but someday we hope to get
rid of that and move checking into QAPISchema*.check().  The
two asserts added here make sure any refactoring still catches
problems, and makes it locally obvious why we can iterate over
only type.members without worrying about type.variants.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1458254921-17042-2-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi-commands.py | 3 ++-
 scripts/qapi-event.py    | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index f44e01f..edcbd10 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -2,7 +2,7 @@
 # QAPI command marshaller generator
 #
 # Copyright IBM, Corp. 2011
-# Copyright (C) 2014-2015 Red Hat, Inc.
+# Copyright (C) 2014-2016 Red Hat, Inc.
 #
 # Authors:
 #  Anthony Liguori <aliguori@us.ibm.com>
@@ -30,6 +30,7 @@ def gen_call(name, arg_type, ret_type):
 
     argstr = ''
     if arg_type:
+        assert not arg_type.variants
         for memb in arg_type.members:
             if memb.optional:
                 argstr += 'has_%s, ' % c_name(memb.name)
diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py
index fb579dd..c03cb78 100644
--- a/scripts/qapi-event.py
+++ b/scripts/qapi-event.py
@@ -59,6 +59,7 @@ def gen_event_send(name, arg_type):
                  name=name)
 
     if arg_type and arg_type.members:
+        assert not arg_type.variants
         ret += mcgen('''
     qov = qmp_output_visitor_new();
     v = qmp_output_get_visitor(qov);
-- 
2.4.3
