[PATCH 1 of 2 V2] util: add a way to issue deprecation warning without a UI object

[Yuya Nishihara]

On Sat, 8 Apr 2017 11:37:20 +0200, Pierre-Yves David wrote:
> On 04/08/2017 10:16 AM, Yuya Nishihara wrote:
> > On Fri, 7 Apr 2017 19:03:55 +0200, Pierre-Yves David wrote:
> >> On 04/06/2017 05:44 PM, Yuya Nishihara wrote:
> >>> On Thu, 6 Apr 2017 16:09:07 +0200, Pierre-Yves David wrote:
> >>>>> If dirty hack allowed, I would do something like the following:
> >>>>>
> >>>>>   # util.py
> >>>>>   def _deprecwarn(msg, version):
> >>>>>       pass
> >>>>>
> >>>>>   # somewhere ui is available, maybe in dispatch.py
> >>>>>   util._deprecwarn = ui.deprecwarn
> >>>>
> >>>> That is a diry hack. I would prefer we did not used it.
> >>>
> >>> Yeah, that is dirty and I don't like it. But I'm okay with it as long as
> >>> it is a temporary hack.
> >>
> >> If you think the dirty hack is worth the potential extra exposure, I'm
> >> fine with it.
> >>
> >> However, I'm confused about your usage of "temporary hack" here. Why are
> >> you using temporary?
> >
> > I suppose the hack will hopefully disappear with the vfs compat layer. I'm not
> > sure if a permanent one is necessary.
> 
> I think this kind of needs will appears again in the future. So I would 
> not flag the solution as temporary. I would have made the function local 
> to the scmutil module.
> 
> So I would rather have a long terms solution. What do you think?

If we need less ad-hoc one, I would add a global flag to enable deprecwarn
and set it only by global configuration (i.e. ui, not lui nor repo.ui.)
And perhaps will remove ui.deprecwarn() in favor of util.deprecwarn().