[bug#68266] [PATCH 7/7] packages: rust: Memoize make-rust-sysroot results.

[Christopher Baines]

To ensure that it just returns a single package record for some given
arguments, as this helps to avoid poor performance of the store connection
object cache.

* gnu/packages/rust.scm (make-rust-sysroot): Move code to
make-rust-sysroot/implementation.
(make-rust-sysroot/implementation): New variable.

Change-Id: Ibb30c7398328c87c032bb8828635a34ada935167
---
 gnu/packages/rust.scm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/rust.scm b/gnu/packages/rust.scm
index ea95d27476..64cde7ea14 100644
--- a/gnu/packages/rust.scm
+++ b/gnu/packages/rust.scm
@@ -60,6 +60,7 @@ (define-module (gnu packages rust)
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system trivial)
   #:use-module (guix download)
+  #:use-module (guix memoization)
   #:use-module (guix git-download)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
@@ -1057,7 +1058,10 @@ (define-public rust
                             (package-native-inputs base-rust))))))
 
 (define*-public (make-rust-sysroot target)
-  (let ((base-rust rust))
+  (make-rust-sysroot/implementation target rust))
+
+(define make-rust-sysroot/implementation
+  (mlambda (target base-rust)
     (package
       (inherit base-rust)
       (name (string-append "rust-sysroot-for-" target))
-- 
2.41.0