[PATCH -v2 1/2] build: union: Add create-all-directories? parameter to union-build

[Huang Ying]

* guix/build/union.scm (union-build): Add create-all-directories? keyword
  parameter.  To add/remove some files from the directory.
---
 guix/build/union.scm | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/guix/build/union.scm b/guix/build/union.scm
index 6640b5652..6a2a0f546 100644
--- a/guix/build/union.scm
+++ b/guix/build/union.scm
@@ -73,7 +73,8 @@ identical, #f otherwise."
                                   (loop)))))))))))))
 
 (define* (union-build output inputs
-                      #:key (log-port (current-error-port)))
+                      #:key (log-port (current-error-port))
+                      (create-all-directories? #f))
   "Build in the OUTPUT directory a symlink tree that is the union of all
 the INPUTS."
 
@@ -104,8 +105,11 @@ the INPUTS."
   (define (union output inputs)
     (match inputs
       ((input)
-       ;; There's only one input, so just make a link.
-       (symlink* input output))
+       ;; There's only one input, so just make a link unless
+       ;; create-all-directories?.
+       (if (and create-all-directories? (file-is-directory? input))
+           (union-of-directories output inputs)
+           (symlink* input output)))
       (_
        (call-with-values (lambda () (partition file-is-directory? inputs))
          (match-lambda*
-- 
2.12.0