packages: 'package-input-rewriting/spec' optionally replace hidden.

Commit eee95b5a879b7096dffd533f24107cf8926b621e changed package
rewriting to ignore hidden packages. This patch permits the previous use
by adding an option to rewrite hidden packages.

* guix/packages.scm (package-input-rewriting/spec)[rewrite]: When P is
hidden, return it as-is unless #:replace-hidden? has been enabled.
* tests/packages.scm ("package-input-rewriting/spec, replace hidden
package"): New test.
* doc/guix.texi (Defining Package Variants): Update.

Change-Id: I0a7988cac70e0c6b88b0fe6e27c1036fa723e030
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

3 files changed, 26 insertions, 6 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 0d461fb96a..8a6640124c 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -7277,7 +7277,8 @@ build} (@pxref{Additional Build Options, @option{--expression} in
 @command{guix build}}).
 
 @item --file=@var{file}
-build a pack the code within @var{file} evaluates to.
+Build a pack containing the package or other object the code within
+@var{file} evaluates to.
 
 This has the same purpose as the same-named option in @command{guix
 build} (@pxref{Additional Build Options, @option{--file} in
@@ -8679,7 +8680,8 @@ This is exactly what the @option{--with-input} command-line option does
 The following variant of @code{package-input-rewriting} can match packages to
 be replaced by name rather than by identity.
 
-@deffn {Procedure} package-input-rewriting/spec @var{replacements} [#:deep? #t]
+@deffn {Procedure} package-input-rewriting/spec @var{replacements} @
+  [#:deep? #t] [#:replace-hidden? #t]
 Return a procedure that, given a package, applies the given
 @var{replacements} to all the package graph, including implicit inputs
 unless @var{deep?} is false.
@@ -8688,7 +8690,7 @@ unless @var{deep?} is false.
 package specification such as @code{"gcc"} or @code{"guile@@2"}, and
 each procedure takes a matching package and returns a replacement for
 that package.  Matching packages that have the @code{hidden?} property
-set are not replaced.
+set are not replaced unless @var{replace-hidden?} is set to true.
 @end deffn
 
 The example above could be rewritten this way:
diff --git a/guix/packages.scm b/guix/packages.scm
index f373136d22..dbb8597488 100644
--- a/guix/packages.scm
+++ b/guix/packages.scm
@@ -1611,14 +1611,16 @@ package and returns its new name after rewrite."
   (package-mapping rewrite cut?
                    #:deep? deep?))
 
-(define* (package-input-rewriting/spec replacements #:key (deep? #t))
+(define* (package-input-rewriting/spec replacements
+                                       #:key (deep? #t) (replace-hidden? #f))
   "Return a procedure that, given a package, applies the given REPLACEMENTS to
 all the package graph, including implicit inputs unless DEEP? is false.
 
 REPLACEMENTS is a list of spec/procedures pair; each spec is a package
 specification such as \"gcc\" or \"guile@2\", and each procedure takes a
 matching package and returns a replacement for that package.  Matching
-packages that have the 'hidden?' property set are not replaced."
+packages that have the 'hidden?' property set are not replaced unless
+REPLACE-HIDDEN? is set to true."
   (define table
     (fold (lambda (replacement table)
             (match replacement
@@ -1647,7 +1649,8 @@ packages that have the 'hidden?' property set are not replaced."
 
   (define (rewrite p)
     (if (or (assq-ref (package-properties p) replacement-property)
-            (hidden-package? p))
+            (and (not replace-hidden?)
+                 (hidden-package? p)))
         p
         (match (find-replacement p)
           (#f p)
diff --git a/tests/packages.scm b/tests/packages.scm
index a623628447..7c28e75c45 100644
--- a/tests/packages.scm
+++ b/tests/packages.scm
@@ -1628,6 +1628,21 @@
     (match (delete-duplicates pythons eq?)
       ((p) (eq? p python)))))
 
+(test-assert "package-input-rewriting/spec, replace hidden package"
+  ;; Rewrite hidden packages when requested.
+  (let* ((python  (hidden-package python))
+         (p0      (dummy-package "chbouib"
+                    (build-system trivial-build-system)
+                    (inputs (list python))))
+         (rewrite (package-input-rewriting/spec
+                   `(("python" . ,(const sed)))
+                   #:replace-hidden? #t))
+         (p1      (rewrite p0)))
+    (match (package-inputs p1)
+      ((("python" python))
+       (and (string=? (package-full-name python)
+                      (package-full-name sed)))))))
+
 (test-equal "package-input-rewriting/spec, graft"
   (derivation-file-name (package-derivation %store sed))