packages: 'package-transitive-supported-systems' accounts for implicit inputs.

Reported by Federico Beffa.

* guix/packages.scm (package-transitive-supported-systems): Use
  bag-direct-inputs + package->bag rather than package-direct-inputs.
* tests/packages.scm ("package-transitive-supported-systems"): Add
  explicit 'build-system' field to each 'dummy-package' form.
  ("package-transitive-supported-systems, implicit inputs"): New test.

2 files changed, 33 insertions, 10 deletions

diff --git a/guix/packages.scm b/guix/packages.scm
index f278db50f1..7d4696fb5e 100644
--- a/guix/packages.scm
+++ b/guix/packages.scm
@@ -579,7 +579,7 @@ supported by its dependencies."
             (_
              systems)))
         (package-supported-systems package)
-        (package-direct-inputs package)))
+        (bag-direct-inputs (package->bag package))))
 
 (define (bag-direct-inputs bag)
   "Same as 'package-direct-inputs', but applied to a bag."
diff --git a/tests/packages.scm b/tests/packages.scm
index b50551e963..a93ee66831 100644
--- a/tests/packages.scm
+++ b/tests/packages.scm
@@ -128,21 +128,44 @@
     ("y")                                         ;c
     ("y")                                         ;d
     ("y"))                                        ;e
-  (let* ((a (dummy-package "a" (supported-systems '("x" "y" "z"))))
-         (b (dummy-package "b" (supported-systems '("x" "y"))
-               (inputs `(("a" ,a)))))
-         (c (dummy-package "c" (supported-systems '("y" "z"))
-               (inputs `(("b" ,b)))))
-         (d (dummy-package "d" (supported-systems '("x" "y" "z"))
-               (inputs `(("b" ,b) ("c" ,c)))))
-         (e (dummy-package "e" (supported-systems '("x" "y" "z"))
-               (inputs `(("d" ,d))))))
+  ;; Use TRIVIAL-BUILD-SYSTEM because it doesn't add implicit inputs and thus
+  ;; doesn't restrict the set of supported systems.
+  (let* ((a (dummy-package "a"
+              (build-system trivial-build-system)
+              (supported-systems '("x" "y" "z"))))
+         (b (dummy-package "b"
+              (build-system trivial-build-system)
+              (supported-systems '("x" "y"))
+              (inputs `(("a" ,a)))))
+         (c (dummy-package "c"
+              (build-system trivial-build-system)
+              (supported-systems '("y" "z"))
+              (inputs `(("b" ,b)))))
+         (d (dummy-package "d"
+              (build-system trivial-build-system)
+              (supported-systems '("x" "y" "z"))
+              (inputs `(("b" ,b) ("c" ,c)))))
+         (e (dummy-package "e"
+              (build-system trivial-build-system)
+              (supported-systems '("x" "y" "z"))
+              (inputs `(("d" ,d))))))
     (list (package-transitive-supported-systems a)
           (package-transitive-supported-systems b)
           (package-transitive-supported-systems c)
           (package-transitive-supported-systems d)
           (package-transitive-supported-systems e))))
 
+(test-equal "package-transitive-supported-systems, implicit inputs"
+  %supported-systems
+
+  ;; Here GNU-BUILD-SYSTEM adds implicit inputs that build only on
+  ;; %SUPPORTED-SYSTEMS.  Thus the others must be ignored.
+  (let ((p (dummy-package "foo"
+             (build-system gnu-build-system)
+             (supported-systems
+              `("does-not-exist" "foobar" ,@%supported-systems)))))
+    (package-transitive-supported-systems p)))
+
 (test-skip (if (not %store) 8 0))
 
 (test-assert "package-source-derivation, file"