04/07: guix system: init: Overwrite the items in the target store.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit 78acff7c11507c68b63ad289b2bbe396602b9dcf
Author: Ludovic Courtès <address@hidden>
Date:   Wed Jun 10 10:31:47 2015 +0200

    guix system: init: Overwrite the items in the target store.
    
    Fixes <http://bugs.gnu.org/20722>.
    Reported by Eric Bavier <address@hidden>.
    
    * guix/scripts/system.scm (copy-item): Check whether DEST exists and remove 
it
      if it does.
---
 guix/scripts/system.scm |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm
index f7c9d83..aa9b3f8 100644
--- a/guix/scripts/system.scm
+++ b/guix/scripts/system.scm
@@ -76,6 +76,13 @@
     (let ((dest  (string-append target item))
           (state (string-append target "/var/guix")))
       (format log-port "copying '~a'...~%" item)
+
+      ;; Remove DEST if it exists to make sure that (1) we do not fail badly
+      ;; while trying to overwrite it (see <http://bugs.gnu.org/20722>), and
+      ;; (2) we end up with the right contents.
+      (when (file-exists? dest)
+        (delete-file-recursively dest))
+
       (copy-recursively item dest
                         #:log (%make-void-port "w"))