From a831ff6bc3f92ab4ecf6135e4d6386f14189ad06 Mon Sep 17 00:00:00 2001 From: Mathieu Othacehe Date: Wed, 10 Mar 2021 12:08:10 +0100 Subject: inferior: Use a safe symlink monadic procedure. This is a follow-up of 6ee7e3d26b8f5d2a234518cc2ab1bfeba7cd7c18. * guix/inferior.scm (cached-channel-instance): Introduce "symlink/safe" and use it instead of symlink. Remove the duplicated "file-exists?" call. --- guix/inferior.scm | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/guix/inferior.scm b/guix/inferior.scm index 259be3f27d..f977f8386e 100644 --- a/guix/inferior.scm +++ b/guix/inferior.scm @@ -740,8 +740,16 @@ determines whether CHANNELS are authenticated." (string-append directory "/" file)) (scandir directory base32-encoded-sha256?))) + (define (symlink/safe old new) + (catch 'system-error + (lambda () + (symlink old new)) + (lambda args + (unless (= EEXIST (system-error-errno args)) + (apply throw args))))) + (define symlink* - (lift2 symlink %store-monad)) + (lift2 symlink/safe %store-monad)) (define add-indirect-root* (store-lift add-indirect-root)) @@ -766,9 +774,8 @@ determines whether CHANNELS are authenticated." (built-derivations (list profile)) ;; Note: Caching is fine even when AUTHENTICATE? is false because ;; we always call 'latest-channel-instances?'. - (unless (file-exists? cached) - (symlink* (derivation->output-path profile) cached) - (add-indirect-root* cached)) + (symlink* (derivation->output-path profile) cached) + (add-indirect-root* cached) (return cached)))))) (define* (inferior-for-channels channels -- cgit 1.4.1