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From: Eric Blake <eblake@redhat.com>
Message-ID: <66bcdf04-74e6-34c5-b34c-6fc06a5c6a7d@redhat.com>
Date: Mon, 15 Oct 2018 13:49:33 -0500
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Subject: Re: [Qemu-devel] [PATCH v2 01/35] error: Fix use of error_prepend()
 with &error_fatal, &error_abort
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To: Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org
Cc: Fei Li <fli@suse.com>

On 10/15/18 6:52 AM, Markus Armbruster wrote:
>>>From include/qapi/error.h:
> 
>    * Pass an existing error to the caller with the message modified:
>    *     error_propagate(errp, err);
>    *     error_prepend(errp, "Could not frobnicate '%s': ", name);
> 
> Fei Li pointed out that doing error_propagate() first doesn't work
> well when @errp is &error_fatal or &error_abort: the error_prepend()
> is never reached.
> 
> Since I doubt fixing the documentation will stop people from getting
> it wrong, introduce error_propagate_prepend(), in the hope that it
> lures people away from using its constituents in the wrong order.
> Update the instructions in error.h accordingly.
> 
> Convert existing error_prepend() next to error_propagate to
> error_propagate_prepend().  If any of these get reached with
> &error_fatal or &error_abort, the error messages improve.  I didn't
> check whether that's the case anywhere.
> 
> Cc: Fei Li <fli@suse.com>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---

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

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org