From b9a31d90e907db0a593ec80aacc35a0523a009f6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= Date: Fri, 29 Aug 2014 14:53:15 +0200 Subject: [PATCH] offload: Ignore EEXIST when registering a .drv as a GC root. Fixes . Reported by Mark H Weaver . * guix/scripts/offload.scm (register-gc-root)[script]: Wrap 'symlink' call in "catch 'system-error", and ignore EEXIST errors. --- guix/scripts/offload.scm | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/guix/scripts/offload.scm b/guix/scripts/offload.scm index c17de34acc..b3b502425c 100644 --- a/guix/scripts/offload.scm +++ b/guix/scripts/offload.scm @@ -316,8 +316,17 @@ (define script (let ((root-directory (string-append %state-directory "/gcroots/tmp"))) (false-if-exception (mkdir root-directory)) - (symlink ,file - (string-append root-directory "/" ,%gc-root-file))))) + (catch 'system-error + (lambda () + (symlink ,file + (string-append root-directory "/" ,%gc-root-file))) + (lambda args + ;; If FILE already exists, we can assume that either it's a stale + ;; reference (which is fine), or another process is already + ;; building the derivation represented by FILE (which is fine + ;; too.) Thus, do nothing in that case. + (unless (= EEXIST (system-error-errno args)) + (apply throw args))))))) (let ((pipe (remote-pipe machine OPEN_READ `("guile" "-c" ,(object->string script)))))