Re: [Qemu-devel] [PATCH 04/11] qerror: Eliminate QERR_DEVICE_NOT_FOUND

[Peter Maydell]

On 15 June 2015 at 16:18, Luiz Capitulino <address@hidden> wrote:
> On Sat, 13 Jun 2015 16:20:51 +0200
> Markus Armbruster <address@hidden> wrote:
>
>> Error classes other than ERROR_CLASS_GENERIC_ERROR should not be used
>> in new code.  Hiding them in QERR_ macros makes new uses hard to spot.
>> Fortunately, there's just one such macro left.  Eliminate it with this
>> coccinelle semantic patch:
>>
>>     @@
>>     expression EP, E;
>>     @@
>>     -error_set(EP, QERR_DEVICE_NOT_FOUND, E)
>>     +error_set(EP, ERROR_CLASS_DEVICE_NOT_FOUND, "Device '%s' not found", E)
>
> This is a bit minor, but I think I'd have created a new function instead,
> say error_set_enodev(). This avoids all the duplication. But I'm not asking
> you to change, as the patch is good and this can be done in the future if
> we so want.

The thing about that kind of generic set-an-error function is that
it encourages people to use it rather than providing an error message
that's more specific and helpful for the particular situation. That
might not be a problem in this patch (I haven't read it), but I mention
it because I have a patch onlist elsewhere which undoes a bit of
"generic error based on an errno" in favour of being more specific
about why something didn't work.

thanks
-- PMM