flake/dev/diff-plugins: make a package output; ci: use diff-plugins from package output

.github/workflows/pr-merged.yml

@@ -79,7 +79,6 @@ jobs:
       - name: Install Nix
         uses: cachix/install-nix-action@v31
         with:
-          nix_path: nixpkgs=channel:nixpkgs-unstable
           extra_nix_config: |
             accept-flake-config = true
 
@@ -124,7 +123,7 @@ jobs:
           head: ${{ github.event.pull_request.head.sha }}
         run: |
           out=$(mktemp)
-          ./flake/dev/diff-plugins.py --compact "$base" "$head" > "$out"
+          nix run .#diff-plugins --compact "$base" "$head" > "$out"
           {
             echo -n 'json='
             jq -c . < "$out"
@@ -138,7 +137,7 @@ jobs:
           head: ${{ github.event.pull_request.merge_commit_sha }}
         run: |
           out=$(mktemp)
-          ./flake/dev/diff-plugins.py --compact "$base" "$head" > "$out"
+          nix run .#diff-plugins --compact "$base" "$head" > "$out"
           {
             echo -n 'json='
             jq -c . < "$out"

flake/default.nix

@@ -51,6 +51,7 @@
       packages = lib.optionalAttrs (partitionStack == [ ]) {
         # Propagate `packages` from the `dev` partition:
         inherit (config.partitions.dev.module.flake.packages.${system})
+          diff-plugins
           list-plugins
           ;
       };

flake/dev/default.nix

@@ -2,6 +2,7 @@
 {
   imports = [
     ./devshell.nix
+    ./diff-plugins
     ./list-plugins
     ./package-tests.nix
     ./template-tests.nix

flake/dev/devshell.nix

@@ -115,11 +115,6 @@
               command = ''${./new-plugin.py} "$@"'';
               help = "Create a new plugin";
             }
-            {
-              name = "diff-plugins";
-              command = ''${./diff-plugins.py} "$@"'';
-              help = "Compare available plugins with another nixvim commit";
-            }
           ];
       };
     };

flake/dev/diff-plugins/default.nix

@@ -0,0 +1,30 @@
+{
+  perSystem =
+    {
+      lib,
+      pkgs,
+      ...
+    }:
+    let
+      package = pkgs.writers.writePython3Bin "diff-plugins" {
+        # Disable flake8 checks that are incompatible with the ruff ones
+        flakeIgnore = [
+          # Thinks shebang is a block comment
+          "E265"
+          # line too long
+          "E501"
+        ];
+      } (builtins.readFile ./diff-plugins.py);
+    in
+    {
+      packages.diff-plugins = package;
+
+      devshells.default.commands = [
+        {
+          name = "diff-plugins";
+          command = ''${lib.getExe package} "$@"'';
+          help = "Compare available plugins with another nixvim commit";
+        }
+      ];
+    };
+}