Re: [Qemu-trivial] [PATCH for-1.4 v2 4/6] qemu-option: Disable two helpful messages that got broken recently

[Markus Armbruster <armbru@redhat.com>]

Luiz Capitulino <lcapitulino@redhat.com> writes:

> On Fri,  8 Feb 2013 17:17:10 +0100
> Markus Armbruster <armbru@redhat.com> wrote:
>
>> commit 8be7e7e4 and commit ec7b2ccb messed up the ordering of error
>> message and the helpful explanation that should follow it, like this:
>> 
>>     $ qemu-system-x86_64 --nodefaults -S --vnc :0 --chardev null,id=,
>>     Identifiers consist of letters, digits, '-', '.', '_', starting
>> with a letter.
>>     qemu-system-x86_64: -chardev null,id=,: Parameter 'id' expects
>> an identifier
>> 
>>     $ qemu-system-x86_64 --nodefaults -S --vnc :0 --machine
>> kvm_shadow_mem=dunno
>>     You may use k, M, G or T suffixes for kilobytes, megabytes,
>> gigabytes and terabytes.
>>     qemu-system-x86_64: -machine kvm_shadow_mem=dunno: Parameter
>> kvm_shadow_mem' expects a size
>> 
>> Pity.  Disable them for now.
>
> Oops, sorry. I think I'd prefer to drop them, but as this fixes the problem:
>
> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
>
> Also, the real problem here is that general functions like parse_option_size()
> should never assume/try to guess in which context they're running. So, the
> best solution here is either to have a general enough error message that's
> not tied to any context, or let up layers (say vl.c) concatenate the
> context-dependent part of the error message.

I'm open to suggestions on how to better code the pattern "report an
error (a short string without newlines) together with some explanation
or hint (possibly longer string, newlines okay).