derivations: 'derivation' and related procedures return a single value.

* guix/derivations.scm (derivation->output-path,
  derivation->output-paths): New procedures.
  (derivation-path->output-path): Use 'derivation->output-path'.
  (derivation-path->output-paths): Use 'derivation->output-paths'.
  (derivation): Accept 'derivation?' objects as inputs.  Return a single
  value.
  (build-derivations): New procedure.
  (compiled-modules): Use 'derivation->output-paths'.
  (build-expression->derivation)[source-path]: Add case for when the
  input matches 'derivation?'.
  [prologue]: Accept 'derivation?' objects in INPUTS.
  [mod-dir, go-dir]: Use 'derivation->output-path'.
* guix/download.scm (url-fetch): Adjust to the single-value return.
* guix/packages.scm (package-output): Use 'derivation->output-path'.
* guix/scripts/build.scm (guix-build): When the argument is
  'derivation-path?', pass it through 'read-derivation'.
  Use 'derivation-file-name' to print out the .drv file names, and to
  register them.  Use 'derivation->output-path' instead of
  'derivation-path->output-path'.
* guix/scripts/package.scm (roll-back): Adjust to the single-value
  return.
  (guix-package): Use 'derivation->output-path'.
* guix/ui.scm (show-what-to-build): Adjust to deal with 'derivation?'
  objects instead of .drv file names.
* gnu/system/grub.scm (grub-configuration-file): Use
  'derivation->output-path' instead of 'derivation-path->output-path'.
* gnu/system/vm.scm (qemu-image, system-qemu-image): Likewise.
* tests/builders.scm, tests/derivations.scm, tests/packages.scm,
  tests/store.scm, tests/union.scm: Adjust to the new calling
  convention.
* doc/guix.texi (Defining Packages, The Store, Derivations): Adjust
  accordingly.

1 files changed, 17 insertions, 17 deletions

diff --git a/guix/ui.scm b/guix/ui.scm
index 720d01be02..293730308e 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -210,27 +210,27 @@ derivations listed in DRV.  Return #t if there's something to build, #f
 otherwise.  When USE-SUBSTITUTES?, check and report what is prerequisites are
 available for download."
   (let*-values (((build download)
-                 (fold2 (lambda (drv-path build download)
-                          (let ((drv (call-with-input-file drv-path
-                                       read-derivation)))
-                            (let-values (((b d)
-                                          (derivation-prerequisites-to-build
-                                           store drv
-                                           #:use-substitutes?
-                                           use-substitutes?)))
-                              (values (append b build)
-                                      (append d download)))))
+                 (fold2 (lambda (drv build download)
+                          (let-values (((b d)
+                                        (derivation-prerequisites-to-build
+                                         store drv
+                                         #:use-substitutes?
+                                         use-substitutes?)))
+                            (values (append b build)
+                                    (append d download))))
                         '() '()
                         drv))
                 ((build)                          ; add the DRV themselves
                  (delete-duplicates
-                  (append (remove (compose (lambda (out)
-                                             (or (valid-path? store out)
-                                                 (and use-substitutes?
-                                                      (has-substitutes? store
-                                                                        out))))
-                                           derivation-path->output-path)
-                                  drv)
+                  (append (map derivation-file-name
+                               (remove (lambda (drv)
+                                         (let ((out (derivation->output-path
+                                                     drv)))
+                                           (or (valid-path? store out)
+                                               (and use-substitutes?
+                                                    (has-substitutes? store
+                                                                      out)))))
+                                       drv))
                           (map derivation-input-path build))))
                 ((download)                   ; add the references of DOWNLOAD
                  (if use-substitutes?