| Message ID | 1383766420-20745-3-git-send-email-xiawenc@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On 11/06/2013 12:33 PM, Wenchao Xia wrote: > It is possible to reach default case, when an union have a enum > discriminator, so don't abort() but report the error message. > > Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> > --- > scripts/qapi-visit.py | 14 ++++++++++++-- > 1 files changed, 12 insertions(+), 2 deletions(-) I still think this is not ideal. You are proposing a runtime error: > + # Tell caller the value is invalid, since the discriminator value maybe an > + # unmapped enum value. > ret += mcgen(''' > default: > - abort(); > + error_setg(&err, > + "Invalid discriminator value %(pi)s for %(name)s", > + (*obj)->kind); > + break; > } whereas I'm requesting a compile-time error - it is much easier for maintenance reasons to have the generator require up-front that all enum values are covered, and loudly complain if an enum type is extended without also extending the use of that enum type in a union, than it is to silently generate a runtime error and wait for the bug reports several weeks down the road.
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py index c39e628..b3d3af8 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -223,6 +223,8 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error ** c_type = type_name(members[key]), c_name = c_fun(key)) + # Only support input visitor for an anon union now, and it is not possible + # to reach default, so abort() here, see the logic for (*obj)->kind ret += mcgen(''' default: abort(); @@ -312,15 +314,23 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error ** c_type=type_name(members[key]), c_name=c_fun(key)) + # Tell caller the value is invalid, since the discriminator value maybe an + # unmapped enum value. ret += mcgen(''' default: - abort(); + error_setg(&err, + "Invalid discriminator value %(pi)s for %(name)s", + (*obj)->kind); + break; } } error_propagate(errp, err); err = NULL; } -''') +''', + pi="%d", + name=name) + pop_indent() ret += mcgen(''' /* Always call end_struct if start_struct succeeded. */
It is possible to reach default case, when an union have a enum discriminator, so don't abort() but report the error message. Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com> --- scripts/qapi-visit.py | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-)