[libvirt] [PATCH v2 02/42] util: handle missing switch enum cases

[Daniel P. Berrangé]

On Tue, Feb 20, 2018 at 01:05:23PM +0100, Andrea Bolognani wrote:
> On Tue, 2018-02-20 at 11:25 +0000, Daniel P. Berrangé wrote:
> > > Yesterday I argued in a different thread that it would be better
> > > to include the enum name in the error message, since that's useful
> > > information for developers whereas users 1) should never see this
> > > kind of error to begin with and 2) when they do, their only course
> > > of action is reporting the issue anyway.
> > 
> > How about we standard it via a special API
> > 
> >    virReportErrorEnumRange(virDomainControllerModelUSB, val->type);
> > 
> > and map this through to a VIR_ERR_ENUM_RANGE error code, with a fixed
> > string format.
> > 
> >    "Value '%d' out of range for enum %s"
> 
> Sounds like a good idea! We could even add something like
> 
>   This is a bug in libvirt, please report it.
> 
> or similar to make it clear that the user is not at fault.

I don't think we should go down that road - most errors are not the user's
fault - they the fault of some component somewhere in the stack.

> 
> Not sure about using a separate error code rather than the existing
> INTERNAL_ERROR, though: it seems like it would not really buy us
> anything.
> 
> -- 
> Andrea Bolognani / Red Hat / Virtualization

Regards,
Daniel
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