On Fri, Jul 6, 2012 at 2:28 PM, Kirill Elagin <[email protected]> wrote: > 2012/7/6 Mathijs Kwik <[email protected]> >> >> Yeah I saw those comments too, but I can't see how that would work. >> Because the "original" (pkgsOrig) set is built by passing pkgs (the >> final set) to pkgsFun. >> In other words, the set references itself, which is perfectly normal >> in a lazy setting. >> The notion of "original" makes sense for the attributes that get >> overwritten, but for the rest, I would expect a "shine through". > > > As Shea already pointed out there is ``__overrides`` dark magic involved. > Basically, your overrides are never added to pkgs directly, I mean, there is > no something like "pkgs = overrides // origPkgs".
The documentation clearly states __overrides is more powerful than //, because // would leave the original set looking at the old values when introspecting itself. With __overrides, they _do_ get added to the set, and even replace the items inside, so other items in the set see the new values. So this __overrides magic is indeed why I would expect this to work, as it gives a consistent attrset which can look at itself and see the (new) consistent view. > > -- > Кирилл Елагин > _______________________________________________ nix-dev mailing list [email protected] http://lists.science.uu.nl/mailman/listinfo/nix-dev
