Hi, Ludovic Courtès <l...@gnu.org> writes:
> Ulf Herrman <strin...@tilde.club> skribis: > >> -(define (build-system-with-package-mapping bs rewrite) >> +(define (build-system-with-package-mapping bs rewrite-input >> rewrite-argument) >> "Return a variant of BS, a build system, that rewrites a bag's inputs by >> passing them through REWRITE, a procedure that takes an input tuplet and >> returns a \"rewritten\" input tuplet." >> @@ -1442,9 +1442,10 @@ (define (build-system-with-package-mapping bs rewrite) >> (let ((lowered (apply lower args))) >> (bag >> (inherit lowered) >> - (build-inputs (map rewrite (bag-build-inputs lowered))) >> - (host-inputs (map rewrite (bag-host-inputs lowered))) >> - (target-inputs (map rewrite (bag-target-inputs lowered)))))) >> + (build-inputs (map rewrite-input (bag-build-inputs lowered))) >> + (host-inputs (map rewrite-input (bag-host-inputs lowered))) >> + (target-inputs (map rewrite-input (bag-target-inputs lowered))) >> + (arguments (map rewrite-argument (bag-arguments lowered)))))) > > Aah, now I understand. :-) > > It’s indeed the case that arguments can capture references to packages > that won’t be caught by ‘package-mapping’. For instance, if you write: > > (package > … > (arguments (list … #~(whatever #$coreutils)))) > > … then ‘coreutils’ here cannot be replaced. > > To address this, the recommendation is to always add dependencies to > input fields and to use self-references within arguments. The example > above should be written like this: > > (package > … > (arguments > (list … #~(whatever #$(this-package-input "coreutils"))))) > > It’s just a recommendation and one can perfectly ignore it, and I > suppose that was the impetus for this patch. > > This is one of the things discussed while designing this change: > > https://guix.gnu.org/en/blog/2021/the-big-change/ > (search for “self-referential records”) > > https://issues.guix.gnu.org/49169 > > My take was and still is that it’s an acceptable limitation. Packagers > need to follow the guideline above if they want proper support for > rewriting, ‘guix graph’, and other tools. > > WDYT? But not all packages found in a bag come from inputs; they may be provided as an argument to the build system (cmake, meson, qt, etc. all allow for this). -- Thanks, Maxim
