From cd856a327cf13f7d19ad98e1503c2aaf2b3bbda3 Mon Sep 17 00:00:00 2001
From: Matt Sturgeon <matt@sturgeon.me.uk>
Date: Wed, 9 Jul 2025 21:54:15 +0100
Subject: [PATCH] ci/tag-maintainers: split nix into separate file

---
 ci/tag-maintainers/extract-maintainers.nix | 31 ++++++++++++++++
 ci/tag-maintainers/extract-maintainers.py  | 42 +++-------------------
 2 files changed, 36 insertions(+), 37 deletions(-)
 create mode 100644 ci/tag-maintainers/extract-maintainers.nix

diff --git a/ci/tag-maintainers/extract-maintainers.nix b/ci/tag-maintainers/extract-maintainers.nix
new file mode 100644
index 00000000..8a9c6612
--- /dev/null
+++ b/ci/tag-maintainers/extract-maintainers.nix
@@ -0,0 +1,31 @@
+{
+  nixvim ? import ../..,
+  lib ? nixvim.inputs.nixpkgs.lib,
+  changedFilesJson ? throw "provide either changedFiles or changedFilesJson",
+  changedFiles ? builtins.fromJSON changedFilesJson,
+}:
+let
+  emptyConfig = nixvim.lib.nixvim.evalNixvim {
+    modules = [ { _module.check = false; } ];
+    extraSpecialArgs.pkgs = null;
+  };
+  inherit (emptyConfig.config.meta) maintainers;
+
+  # Find maintainers for files that match changed plugin directories
+  relevantMaintainers = lib.concatLists (
+    lib.mapAttrsToList (
+      path: maintainerList:
+      let
+        matchingFiles = lib.filter (file: lib.hasSuffix (dirOf file) path) changedFiles;
+      in
+      if matchingFiles != [ ] then maintainerList else [ ]
+    ) maintainers
+  );
+
+  # Extract GitHub usernames
+  githubUsers = lib.concatMap (
+    maintainer: if maintainer ? github then [ maintainer.github ] else [ ]
+  ) relevantMaintainers;
+
+in
+lib.unique githubUsers
diff --git a/ci/tag-maintainers/extract-maintainers.py b/ci/tag-maintainers/extract-maintainers.py
index 199ea3ee..fd16730e 100755
--- a/ci/tag-maintainers/extract-maintainers.py
+++ b/ci/tag-maintainers/extract-maintainers.py
@@ -10,14 +10,15 @@ import argparse
 import json
 import subprocess
 import sys
+from pathlib import Path
 from typing import List
 
 
-def run_nix_eval(expr: str) -> str:
+def run_nix_eval(file: str, *args: str) -> str:
     """Run a Nix evaluation expression and return the result."""
     try:
         result = subprocess.run(
-            ["nix", "eval", "--impure", "--json", "--expr", expr],
+            ["nix-instantiate", "--eval", "--strict", "--json", file] + list(args),
             capture_output=True,
             text=True,
             check=True,
@@ -37,42 +38,9 @@ def extract_maintainers(changed_files: List[str], pr_author: str) -> List[str]:
 
     print("Finding maintainers for changed files...", file=sys.stderr)
 
+    file = Path(__file__).parent / "extract-maintainers.nix"
     changed_files_nix = "[ " + " ".join(f'"{f}"' for f in changed_files) + " ]"
-
-    nix_expr = f"""
-    let
-      nixvim = import ./.;
-      lib = nixvim.inputs.nixpkgs.lib;
-      emptyConfig = nixvim.lib.nixvim.evalNixvim {{
-        modules = [ {{ _module.check = false; }} ];
-        extraSpecialArgs.pkgs = null;
-      }};
-      inherit (emptyConfig.config.meta) maintainers;
-
-      changedFiles = {changed_files_nix};
-
-      # Find maintainers for files that match changed plugin directories
-      relevantMaintainers = lib.concatLists (
-        lib.mapAttrsToList (path: maintainerList:
-          let
-            matchingFiles = lib.filter (file:
-              lib.hasSuffix (dirOf file) path
-            ) changedFiles;
-          in
-            if matchingFiles != [] then maintainerList else []
-        ) maintainers
-      );
-
-      # Extract GitHub usernames
-      githubUsers = lib.concatMap (maintainer:
-        if maintainer ? github then [ maintainer.github ] else []
-      ) relevantMaintainers;
-
-    in
-      lib.unique githubUsers
-    """
-
-    result = run_nix_eval(nix_expr)
+    result = run_nix_eval(file, "--arg", "changedFiles", changed_files_nix)
 
     try:
         maintainers = json.loads(result)