[oe] [meta-webserver][PATCH] meta-webserver: apache2 allow SYSTEMD_AUTO_ENABLE to be overwritten

[Patrick Ohly]

On Thu, 2017-11-16 at 15:00 -0500, Mark Asselstine wrote:
> On Thursday, November 16, 2017 7:28:06 PM EST Patrick Ohly wrote:
> > On Thu, 2017-11-16 at 10:19 -0500, Mark Asselstine wrote:
> > > The current assignment does not allow a bbappend to be used to
> > > overwrite the SYSTEMD_AUTO_ENABLE value in order to have apache2
> > > auto
> > > start.
> > 
> > Why does SYSTEMD_AUTO_ENABLE_${PN} = "enable" in a apache2_*.bb not
> > work? It works fine for me with wpa-supplicant:
> 
> Sorry. You are correct the bbappend will overwrite it, but this
> requires a bbappend. If this used "?=" you could achieve this in a
> local.conf or similar. 

SYSTEMD_AUTO_ENABLE_pn-wpa-supplicant = "enable" in local.conf also
overrides the = assignment in the .bb file.

> In general if there is a possibility for a value to be desireable to
> overwrite using "?=" makes sense. Thoughts?

I thought the same for a while, but since then I've come around to the
interpretation that for recipe-specific variables, using =? is mostly
just a cosmetic thing. I can't think of a good example where it really
matters in practice.

It's different for global variables which might get set prior to
parsing a recipe (distro config, local.conf). There it makes sense to
not overwrite a potentially existing value.

-- 
Best Regards, Patrick Ohly

The content of this message is my personal opinion only and although
I am an employee of Intel, the statements I make here in no way
represent Intel's position on the issue, nor am I authorized to speak
on behalf of Intel on this matter.