From 9e00f0c852f4ca21057fc82c1c139eb97a6313a4 Mon Sep 17 00:00:00 2001
From: adisbladis <adisbladis@gmail.com>
Date: Thu, 26 Mar 2026 18:58:27 +1300
Subject: [PATCH] rustPlatform.fetchCargoVendor: Don't recompute internal data

Calling nix-prefetch-git.override on every call to fetchCargoVendor is bad for performance.
---
 .../build-support/rust/fetch-cargo-vendor.nix | 31 ++++++++++---------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/pkgs/build-support/rust/fetch-cargo-vendor.nix b/pkgs/build-support/rust/fetch-cargo-vendor.nix
index a02bbd89c7fc..2802bf9e73f1 100644
--- a/pkgs/build-support/rust/fetch-cargo-vendor.nix
+++ b/pkgs/build-support/rust/fetch-cargo-vendor.nix
@@ -22,6 +22,21 @@ let
     ];
   } (builtins.readFile ./replace-workspace-values.py);
 
+  nix-prefetch-git' = nix-prefetch-git.override {
+    git = gitMinimal;
+    # break loop of nix-prefetch-git -> git-lfs -> asciidoctor -> ruby (yjit) -> fetchCargoVendor -> nix-prefetch-git
+    # Cargo does not currently handle git-lfs: https://github.com/rust-lang/cargo/issues/9692
+    git-lfs = null;
+  };
+
+  removedArgs = [
+    "name"
+    "pname"
+    "version"
+    "nativeBuildInputs"
+    "hash"
+  ];
+
   mkFetchCargoVendorUtil =
     name: src:
     writers.writePython3Bin name {
@@ -57,14 +72,6 @@ in
 # TODO: add asserts about pname version and name
 
 let
-  removedArgs = [
-    "name"
-    "pname"
-    "version"
-    "nativeBuildInputs"
-    "hash"
-  ];
-
   vendorStaging = stdenvNoCC.mkDerivation (
     {
       name = "${name}-vendor-staging";
@@ -74,12 +81,7 @@ let
       nativeBuildInputs = [
         fetchCargoVendorUtilV2
         cacert
-        (nix-prefetch-git.override {
-          git = gitMinimal;
-          # break loop of nix-prefetch-git -> git-lfs -> asciidoctor -> ruby (yjit) -> fetchCargoVendor -> nix-prefetch-git
-          # Cargo does not currently handle git-lfs: https://github.com/rust-lang/cargo/issues/9692
-          git-lfs = null;
-        })
+        nix-prefetch-git'
       ]
       ++ nativeBuildInputs;
 
@@ -108,7 +110,6 @@ let
     // removeAttrs args removedArgs
   );
 in
-
 runCommand "${name}-vendor"
   {
     inherit vendorStaging;