Commit 59688fc introduces notable changes: ‘derivation’, ‘build-expression->derivation’, ‘package-derivation’ and similar procedures now return a single value, which is a <derivation> object (previously they would return two values: the .drv file name, and the <derivation> object.) The <derivation> object embeds its .drv file name now:
--8<---------------cut here---------------start------------->8--- scheme@(guile-user)> ,use(gnu packages emacs) scheme@(guile-user)> ,use(guix store) scheme@(guile-user)> ,use(guix packages) scheme@(guile-user)> (define s (open-connection)) scheme@(guile-user)> (package-derivation s emacs) $2 = #<derivation /nix/store/2lfkipm8ydbv3wmj5ryk49nh4hbmwj6w-emacs-24.3.drv => /nix/store/1hkq0q72bki73aa21rakzcffq81vihs1-emacs-24.3 2b2db40> scheme@(guile-user)> (package-cross-derivation s emacs "mips64el-linux-gnuabi64") $3 = #<derivation /nix/store/fc2i5f4kdr3af1h05xjpc7j4h7zqp6k0-emacs-24.3.drv => /nix/store/r478bpdq3mjpci7gsxchjs31xcpgw4f3-emacs-24.3 3af9aa0> --8<---------------cut here---------------end--------------->8--- So the API only sees <derivation> objects now, with the exception of a few RPCs (defined in (guix store)), which still pass .drv file names to the daemon. I think that makes the API much nicer, as can be seen in the tests/* files changed in this patch. It also avoids costs that we previously had, such as repeated calls ‘derivation-path->output-path’, which has to parse a .drv file entirely just to extract its output paths (though the costs were hidden through memoization.) Comments welcome, and please report any problems you may have! Thanks, Ludo’.
