feat(internal): add nix flake dev shell

Author: RobertCraigie

.github/actions/setup-nix/action.yml

@@ -0,0 +1,17 @@
+name: 'Setup Nix'
+description: 'Setup Nix'
+
+runs:
+  using: 'composite'
+
+  steps:
+    - name: Install Nix
+      uses: samueldr/lix-gha-installer-action@7b7f14d320d6aacfb65bd1ef761566b3b69e474c
+
+    - name: Setup Nix cache
+      uses: DeterminateSystems/magic-nix-cache-action@cec65ff6f104850203b152861d3f9e5f1747885d
+      with:
+        use-flakehub: false
+        flakehub-api-server: ''
+        flakehub-cache-server: ''
+        diagnostic-endpoint: ''

.github/workflows/macos-build.yml

@@ -39,35 +39,33 @@ jobs:
       GLIDE_COMPAT: ${{ matrix.arch }}
       MOZ_BUILD_DATE: ${{ inputs.MOZ_BUILD_DATE }}
 
+    defaults:
+      run:
+        shell: nix develop --command bash -e {0}
+
     strategy:
       fail-fast: false
       matrix:
         arch: [aarch64, x86_64]
 
     steps:
-      - name: Debug
-        run: |
-          xcrun --show-sdk-version
-
       - name: Checkout repository
         uses: actions/checkout@08eba0b27e820071cde6df949e0beb9ba4906955 # v4.3.0
         with:
           persist-credentials: false
 
+      - uses: ./.github/actions/setup-nix
+
+      - name: Debug
+        run: |
+          xcrun --show-sdk-version
+
       - name: Configure git
         run: |
           git config --global \
             url."https://github.com/mozilla-firefox/firefox.git".insteadOf \
             "git@github.com:mozilla-firefox/firefox.git"
 
-      - uses: pnpm/action-setup@a7487c7e89a18df4991f7f222e4898a00d66ddda # v4.1.0
-
-      - name: Setup Node.js
-        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version: "24"
-          cache: "pnpm"
-
       - name: Run sccache-cache
         uses: mozilla-actions/sccache-action@7d986dd989559c6ecdb630a3fd2557667be217ad # v0.0.9
         with:
@@ -80,31 +78,12 @@ jobs:
             core.exportVariable('ACTIONS_CACHE_URL', process.env['ACTIONS_CACHE_URL'])
             core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env['ACTIONS_RUNTIME_TOKEN'])
 
-      - name: Install system dependencies
+      - name: Configure rust
         run: |
-          brew update
-          brew install cairo gnu-tar mercurial
-
-          brew uninstall --ignore-dependencies python3.12 -f
-
-          export PATH="$(python3 -m site --user-base)/bin":$PATH
-
-          rm '/usr/local/bin/2to3-3.11' '/usr/local/bin/2to3-3.12' '/usr/local/bin/2to3' || true
-          rm '/usr/local/bin/idle3.11' '/usr/local/bin/idle3.12' '/usr/local/bin/idle3' || true
-          rm '/usr/local/bin/pydoc3.11' '/usr/local/bin/pydoc3.12' '/usr/local/bin/pydoc3' || true
-          rm '/usr/local/bin/python3.11' '/usr/local/bin/python3.12' '/usr/local/bin/python3' || true
-          rm '/usr/local/bin/python3.11-config' '/usr/local/bin/python3.12-config' '/usr/local/bin/python3-config' || true
-
-          brew install watchman
-
-          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain 1.89
-          source $HOME/.cargo/env
-
           if test "$GLIDE_COMPAT" = "aarch64"; then
             rustup target add aarch64-apple-darwin
           else
             rustup target add x86_64-apple-darwin
-            brew install nasm
           fi
 
       - name: Install dependencies
@@ -115,7 +94,6 @@ jobs:
           pnpm bootstrap
 
           cd engine
-          export PATH="$(python3 -m site --user-base)/bin":$PATH
           ./mach --no-interactive bootstrap --application-choice browser --no-system-changes || true
           cd ..
 

flake.lock

@@ -0,0 +1,39 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs?ref=nixos-unstable";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    flake-utils.url = "github:numtide/flake-utils?ref=main";
+  };
+
+  outputs = {
+    nixpkgs,
+    flake-utils,
+    rust-overlay,
+    ...
+  }:
+    flake-utils.lib.eachDefaultSystem (
+      system: let
+        overlays = [(import rust-overlay)];
+        pkgs = import nixpkgs {
+          inherit system overlays;
+        };
+      in {
+        devShell = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            (pnpm.override {nodejs = nodejs_24;})
+            nodejs_24
+            python314
+            uv
+            rust-bin.beta.latest.default
+            watchman
+            cairo
+            gnutar
+            mercurial
+
+            # needed for macos intel builds
+            nasm
+          ];
+        };
+      }
+    );
+}