derivations: Add 'map-derivation'.

* guix/derivations.scm (map-derivation): New procedure.
* tests/derivations.scm ("map-derivation"): New test.

1 files changed, 30 insertions, 0 deletions

diff --git a/tests/derivations.scm b/tests/derivations.scm
index 273db22765..09cf81972c 100644
--- a/tests/derivations.scm
+++ b/tests/derivations.scm
@@ -26,6 +26,7 @@
   #:use-module ((guix packages) #:select (package-derivation))
   #:use-module ((gnu packages) #:select (search-bootstrap-binary))
   #:use-module (gnu packages bootstrap)
+  #:use-module ((gnu packages guile) #:select (guile-1.8))
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-26)
@@ -690,6 +691,35 @@ Deriver: ~a~%"
                                     ((p2 . _)
                                      (string<? p1 p2)))))))))))))
 
+
+(test-equal "map-derivation"
+  "hello"
+  (let* ((joke (package-derivation %store guile-1.8))
+         (good (package-derivation %store %bootstrap-guile))
+         (drv1 (build-expression->derivation %store "original-drv1"
+                                             (%current-system)
+                                             #f   ; systematically fail
+                                             '()
+                                             #:guile-for-build joke))
+         (drv2 (build-expression->derivation %store "original-drv2"
+                                             (%current-system)
+                                             '(call-with-output-file %output
+                                                (lambda (p)
+                                                  (display "hello" p)))
+                                             '()))
+         (drv3 (build-expression->derivation %store "drv-to-remap"
+                                             (%current-system)
+                                             '(let ((in (assoc-ref
+                                                         %build-inputs "in")))
+                                                (copy-file in %output))
+                                             `(("in" ,drv1))
+                                             #:guile-for-build joke))
+         (drv4 (map-derivation %store drv3 `((,drv1 . ,drv2)
+                                             (,joke . ,good))))
+         (out  (derivation->output-path drv4)))
+    (and (build-derivations %store (list (pk 'remapped drv4)))
+         (call-with-input-file out get-string-all))))
+
 (test-end)