From e96d5256872de76699c523e07205dee11cf5043f Mon Sep 17 00:00:00 2001
From: DanConwayDev <DanConwayDev@protonmail.com>
Date: Mon, 2 Mar 2026 09:40:55 +0000
Subject: [PATCH] feat(nix): add bun version check workflow for pull requests

Add a lightweight CI check that compares the bun version in package.json
against the version provided by the nixpkgs revision in flake.lock, using
`nix eval --inputs-from . --raw nixpkgs#bun.version`. This is much cheaper
than a full `nix build` and directly targets the version mismatch problem
that caused #13300 (and recurred on dev with 1.3.10).

The workflow only runs when package.json or flake.lock are touched, and
completes in seconds rather than minutes.

Supersedes #13496 (which used `nix build` as suggested by @gigamonster256).
Also related: #12175 (nix-eval workflow), #13302 (earlier nixpkgs bump).
---
 .github/workflows/nix-bun-version-check.yml | 44 +++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 .github/workflows/nix-bun-version-check.yml

diff --git a/.github/workflows/nix-bun-version-check.yml b/.github/workflows/nix-bun-version-check.yml
new file mode 100644
index 00000000000..43815c3745a
--- /dev/null
+++ b/.github/workflows/nix-bun-version-check.yml
@@ -0,0 +1,44 @@
+name: nix-bun-version-check
+
+on:
+  pull_request:
+    branches: [dev]
+    paths:
+      - "package.json"
+      - "flake.lock"
+      - ".github/workflows/nix-bun-version-check.yml"
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  check:
+    runs-on: blacksmith-4vcpu-ubuntu-2404
+    timeout-minutes: 5
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Setup Nix
+        uses: nixbuild/nix-quick-install-action@v34
+
+      - name: Check bun version matches nixpkgs
+        run: |
+          set -euo pipefail
+
+          pkg_bun=$(jq -r '.packageManager' package.json | sed 's/bun@//')
+          nix_bun=$(nix eval --inputs-from . --raw nixpkgs#bun.version)
+
+          echo "package.json: bun@${pkg_bun}"
+          echo "nixpkgs:      bun@${nix_bun}"
+
+          if [ "$pkg_bun" != "$nix_bun" ]; then
+            echo "::error::Bun version mismatch: package.json requires ${pkg_bun} but nixpkgs provides ${nix_bun}. Update flake.lock (nix flake update nixpkgs) or align package.json."
+            exit 1
+          fi
+
+          echo "Versions match."