[Reproducible-builds] Minimising work needed for this build-path issue

[Daniel Kahn Gillmor]

On Tue 2016-09-06 16:02:00 -0400, Ximin Luo wrote:
> Thanks, I did see this a while ago and forgot about it. However it
> does differ from the current proposal in an important way.
>
> Current proposal (2): GCC should, if SOURCE_ROOT is set and
> debug-prefix-map is not given, *automatically* use this
> variable. There is no opportunity for the user to tell GCC to look at
> a different variable.
>
> OTOH your patch above has GCC read a user-supplied variable. I think
> we want to avoid this, for the same reason that we pushed quite
> heavily for upstreams to support SOURCE_DATE_EPOCH and not their own
> custom command line option. It would also fix packages using gcc but
> not dpkg-buildflags (and for other distros, etc).

ah, right.  I like your constrained version better; hard-coding sensible
practices helps keep everyone on the right track.  It's also much
simpler to argue for this approach if we can point to how
SOURCE_DATE_EPOCH is already supported.

bikeshedding: is SOURCE_ROOT the right name?  I worry a bit about the
different possible meanings of "ROOT" on unix systems.  maybe
SOURCE_BASE_DIR or SOURCE_DIR_ROOT is more descriptive of what we are
describing?  No strong preferences on my side.

> But for sure we can start from the code that you already wrote. :)

yep, that's what i was proposing; i certainly don't mean to suggest that
my original patch is the thing that should be adopted.

   --dkg