Indirect package set flake input

flake.nix

@@ -1,52 +1,53 @@
 {
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs";
-    nixpkgs.follows = "nixpkgs-matrix/nixpkgs";
-    nixpkgs-matrix.url = "github:matrixai/nixpkgs-matrix";
+    nixpkgs-matrix = {
+      type = "indirect";
+      id = "nixpkgs-matrix";
+      inputs.nixpkgs.url =
+        "github:NixOS/nixpkgs?rev=e69e710edfed397959507bcee120ec8a9c7ff03e";
+    };
     flake-utils.url = "github:numtide/flake-utils";
   };
 
-  outputs = { nixpkgs, flake-utils, ... }:
+  outputs = { nixpkgs-matrix, flake-utils, ... }:
     flake-utils.lib.eachDefaultSystem (system:
       let
-        pkgs = import nixpkgs { inherit system; };
+        pkgs = nixpkgs-matrix.legacyPackages.${system};
 
-        shell = { ci ? false }: with pkgs; mkShell {
-          nativeBuildInputs = [
-            nodejs_20
-            shellcheck
-            gitAndTools.gh
-            rustc
-            cargo
-            cmake
-            rustPlatform.bindgenHook
-          ];
-          NIX_DONT_SET_RPATH = true;
-          NIX_NO_SELF_RPATH = true;
-          RUST_SRC_PATH = "${rustPlatform.rustLibSrc}";
-          shellHook = ''
-            echo "Entering $(npm pkg get name)"
-            set -o allexport
-            . ./.env
-            set +o allexport
-            set -v
-            ${
-              lib.optionalString ci
-              ''
-              set -o errexit
-              set -o nounset
-              set -o pipefail
-              shopt -s inherit_errexit
-              ''
-            }
-            mkdir --parents "$(pwd)/tmp"
-            export PATH="$(pwd)/dist/bin:$(npm root)/.bin:$PATH"
-            npm install --ignore-scripts
-            set +v
-          '';
-        };
-      in
-      {
+        shell = { ci ? false }:
+          with pkgs;
+          mkShell {
+            nativeBuildInputs = [
+              nodejs_20
+              shellcheck
+              gitAndTools.gh
+              rustc
+              cargo
+              cmake
+              rustPlatform.bindgenHook
+            ];
+            NIX_DONT_SET_RPATH = true;
+            NIX_NO_SELF_RPATH = true;
+            RUST_SRC_PATH = "${rustPlatform.rustLibSrc}";
+            shellHook = ''
+              echo "Entering $(npm pkg get name)"
+              set -o allexport
+              . ./.env
+              set +o allexport
+              set -v
+              ${lib.optionalString ci ''
+                set -o errexit
+                set -o nounset
+                set -o pipefail
+                shopt -s inherit_errexit
+              ''}
+              mkdir --parents "$(pwd)/tmp"
+              export PATH="$(pwd)/dist/bin:$(npm root)/.bin:$PATH"
+              npm install --ignore-scripts
+              set +v
+            '';
+          };
+      in {
         devShells = {
           default = shell { ci = false; };
           ci = shell { ci = true; };