fix: nix flake build freezes in github action, so try magic nix cache…

… + switch to nixos-stable

.github/workflows/build-artifacts.yml

@@ -10,7 +10,7 @@ on:
     paths-ignore: [ "*.md" ]
 
 jobs:
-  Build-VSIX:
+  Compile-All:
     runs-on: macos-12
     steps:
       - uses: actions/checkout@v4

Vagrantfile

@@ -16,9 +16,11 @@ Vagrant.configure("2") do |config|
 
   config.vm.provision "shell", privileged: false, inline: <<-'SHELL'
     cd /vagrant/
-    echo "statix check &&\
-      nix flake check --impure &&\
-      cp \$(nix build --impure --no-link --print-out-paths)/parigp* ./syntaxes/" |\
+    nix --version
+    df -h
+    echo "statix check && \
+      nix flake check --impure && \
+      cp \$(nix build --impure --no-link --print-out-paths)/parigp* ./syntaxes/" | \
       nix-shell --run bash
   SHELL
 end

flake.nix

@@ -1,7 +1,7 @@
 {
   description = "Builds TextMate grammar for latest version of PARI/GP";
 
-  inputs.nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
+  inputs.nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-stable";
 
   outputs = { self, nixpkgs }:
     let

nixpkgs.nix

@@ -0,0 +1,7 @@
+let
+  lock = (builtins.fromJSON (builtins.readFile ./flake.lock)).nodes.nixpkgs.locked;
+in
+import (fetchTarball {
+  url = "https://github.com/nixos/nixpkgs/archive/${lock.rev}.tar.gz";
+  sha256 = lock.narHash;
+})

shell.nix

@@ -1,4 +1,4 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? (import ./nixpkgs.nix) {} }:
 pkgs.mkShell {
   NIX_CONFIG = "experimental-features = nix-command flakes";
   nativeBuildInputs = with pkgs; [