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From: Markus Armbruster <armbru@redhat.com>
References: <1447836791-369-1-git-send-email-eblake@redhat.com>
	<1447836791-369-36-git-send-email-eblake@redhat.com>
Date: Wed, 18 Nov 2015 19:54:49 +0100
In-Reply-To: <1447836791-369-36-git-send-email-eblake@redhat.com> (Eric
	Blake's message of "Wed, 18 Nov 2015 01:53:10 -0700")
Message-ID: <87twoji1dy.fsf@blackfin.pond.sub.org>
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Subject: Re: [Qemu-devel] [PATCH v12 35/36] qapi: Simplify visits of
	optional fields
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To: Eric Blake <eblake@redhat.com>
Cc: qemu-devel@nongnu.org, Michael Roth <mdroth@linux.vnet.ibm.com>

Eric Blake <eblake@redhat.com> writes:

> None of the visitor callbacks would set an error when testing
> if an optional field was present; make this part of the interface
> contract by eliminating the errp argument.
>
> The resulting generated code has a nice diff:
>
> |-    visit_optional(v, &has_fdset_id, "fdset-id", &err);
> |-    if (err) {
> |-        goto out;
> |-    }
> |-    if (has_fdset_id) {
> |+    visit_optional(v, &has_fdset_id, "fdset-id");
> |+    if (has_fdset_id) {
> |         visit_type_int(v, &fdset_id, "fdset-id", &err);
> |         if (err) {
> |             goto out;
> |         }
> |     }

I think this should be

  |-    visit_optional(v, &has_fdset_id, "fdset-id", &err);
  |-    if (err) {
  |-        goto out;
  |-    }
  |+    visit_optional(v, &has_fdset_id, "fdset-id");
  |     if (has_fdset_id) {
  |         visit_type_int(v, &fdset_id, "fdset-id", &err);
  |         if (err) {
  |             goto out;
  |         }
  |     }

>
> Signed-off-by: Eric Blake <eblake@redhat.com>

Patch looks good.