23/87: substitute: Parse '_NIX_OPTIONS' once.

[guix-commits]

mbakke pushed a commit to branch staging
in repository guix.

commit 007e69756087234de4d9ea896e013e5d0232bd25
Author: Ludovic Courtès <ludo@gnu.org>
AuthorDate: Mon Jan 9 10:27:54 2023 +0100

    substitute: Parse '_NIX_OPTIONS' once.
    
    * guix/scripts/substitute.scm (find-daemon-option): Arrange to call
    'daemon-options' only once.
---
 guix/scripts/substitute.scm | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/guix/scripts/substitute.scm b/guix/scripts/substitute.scm
index 0efa61b0d7..fedb33019d 100755
--- a/guix/scripts/substitute.scm
+++ b/guix/scripts/substitute.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013-2022 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013-2023 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014 Nikita Karetnikov <nikita@karetnikov.org>
 ;;; Copyright © 2018 Kyle Meyer <kyle@kyleam.com>
 ;;; Copyright © 2020 Christopher Baines <mail@cbaines.net>
@@ -706,10 +706,12 @@ substitutes may be unavailable\n")))))
                             (string-drop option=value (+ 1 equal-sign))))))
                  (string-tokenize newline-separated %not-newline)))))
 
-(define (find-daemon-option option)
-  "Return the value of build daemon option OPTION, or #f if it could not be
+(define find-daemon-option
+  (let ((options (delay (daemon-options))))
+    (lambda (option)
+      "Return the value of build daemon option OPTION, or #f if it could not be
 found."
-  (assoc-ref (daemon-options) option))
+      (assoc-ref (force options) option))))
 
 (define %default-substitute-urls
   (match (and=> (or (find-daemon-option "untrusted-substitute-urls") ;client