[libvirt] [Qemu-devel] [PATCH v3 for 2.0] update names in option tables to match with actual command-line spelling

[Markus Armbruster]

Eric Blake <eblake at redhat.com> writes:

> On 03/20/2014 07:07 AM, Amos Kong wrote:
>> We want to establish a mapping between option name and option table,
>> then we can search related option table by option name.
>> 
>> This patch makes all the member name of QemuOptsList to match with
>> actual command-line spelling(option name).
>> 
>> [ Important Note ]
>> 
>> The QemuOptsList member name values are ABI, changing them can break
>> existing -readconfig configuration files.
>> 
>> This patch changes:
>> 
>>     from        to          introduced in
>>     acpi        acpitable   0c764a9 v1.5.0
>>     boot-opts   boot        3d3b830 v1.0
>>     smp-opts    smp         12b7f57 v1.6.0
>> 
>> All three have calcified into ABI already.
>> 
>> I have updated the release note of 2.0
>> http://wiki.qemu.org/ChangeLog/2.0#ABI_breaking
>> 
>> Signed-off-by: Amos Kong <akong at redhat.com>
>> ---
>
> The benefit of this patch is that 'query-command-line-options' gains a
> fix where three bogus entries are replaced by their actual command line
> spelling.  The drawback is that anyone that doesn't pay attention to the
> ABI break announcement, and expects -readconfig and friends to work
> while using the old spelling, is in for a surprise.  But since we have
> prominently documented the change, and since consistency makes life
> nicer, I'm in favor of this patch.
>
> Reviewed-by: Eric Blake <eblake at redhat.com>

I'm not thrilled about the ABI break, but avoiding it would probably
take too much code for too little gain.

How can we prevent future violations of the convention "QemuOptsList
member name matches the name of the (primary) option using it for its
argument"?  Right now, all we have is /* option name */ tacked to the
member.  Which is at best a reminder for those who already know.

I'd ask for a test catching violations if I could think of an easy way
to code it.