From 098e2c0586d10e37f89e1b81dcc9e34ff7b28b1c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christopher=20M=C3=BChl?= <toki@toph.so>
Date: Wed, 4 Mar 2026 12:14:30 +0100
Subject: [PATCH] fix: enable Nix experimental features in docker-build-nix

Add Nix config step to enable nix-command and flakes features
before building. Also configures Attic substituters for faster builds.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---
 docker-build-nix/action.yaml | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/docker-build-nix/action.yaml b/docker-build-nix/action.yaml
index d03a32d..1c7096f 100644
--- a/docker-build-nix/action.yaml
+++ b/docker-build-nix/action.yaml
@@ -42,6 +42,16 @@ inputs:
 runs:
   using: composite
   steps:
+    - name: Configure Nix
+      shell: bash
+      run: |
+        mkdir -p ~/.config/nix
+        cat > ~/.config/nix/nix.conf <<EOF
+        experimental-features = nix-command flakes
+        extra-substituters = https://cache.nixos.org/ ${{ inputs.attic-endpoint }}/ci ${{ inputs.attic-endpoint }}/toph
+        extra-trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= ci:db8ZBxd5cjqoGzOYThRQcxj4XnaqHJZBZw1phCQOiz8= toph:E/oP7KyljH/yprI5LArxNPpSlQCdo29sMOkh3jm53Yg=
+        EOF
+
     - name: Build OCI image with Nix
       shell: bash
       run: |