Re: [Qemu-devel] [PATCH] qom: abort on error in property setter if caller passed errp == NULL

[Eric Blake <eblake@redhat.com>]

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On 11/27/2013 06:24 PM, Igor Mammedov wrote:
> in case if caller setting property doesn't care about error and
> passes in NULL as errp argument but error occurs in property setter,
> it is silently discarded leaving object in undefined state.
> 
> As result it leads to hard to find bugs, so if caller doesn't
> care about error it must be sure that property exists and
> accepts provided value, otherwise it's better to abort early
> since error case couldn't be handled gracefully and find
> invalid usecase early.
> 
> In addition multitude of property setters will be always
> guarantied to have error object present and won't be required

s/guarantied/guaranteed/

> to handle this condition individually.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---

> +out:
> +    if (local_error) {

This says local_error was set...

> +        if (!errp) {
> +            assert_no_error(local_error);

so this assert_no_error() is dead code in its current position.  To be
useful, you probably want:

if (!errp) {
    assert_no_error(local_error);
} else if (local_error) {
    error_propagate(errp, local_error);
}

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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