civodul pushed a commit to branch master
in repository guix.
commit fd951cd543d9f4d3ecfa4570e51797f84e79068b
Author: Ludovic Courtès <l...@gnu.org>
Date: Sun Jun 23 11:40:16 2019 +0200
derivations: 'derivation' preserves pointer equality.
* guix/derivations.scm (derivation): Check if FILE is already in
%DERIVATION-CACHE and return it if it is.
---
guix/derivations.scm | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/guix/derivations.scm b/guix/derivations.scm
index 5c568f2..403e867 100644
--- a/guix/derivations.scm
+++ b/guix/derivations.scm
@@ -873,8 +873,12 @@ derivation. It is kept as-is, uninterpreted, in the
derivation."
(append (map derivation-input-path inputs)
sources)))
(drv* (set-field drv (derivation-file-name) file)))
- (hash-set! %derivation-cache file drv*)
- drv*)))
+ ;; Preserve pointer equality. This improves the performance of
+ ;; 'eq?'-memoization on derivations.
+ (or (hash-ref %derivation-cache file)
+ (begin
+ (hash-set! %derivation-cache file drv*)
+ drv*)))))
(define (invalidate-derivation-caches!)
"Invalidate internal derivation caches. This is mostly useful for
