add dev flake

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -3,3 +3,5 @@ vendor
 coverage.xml
 .phpunit.result.cache
 *.cache
+.direnv
+result

flake.lock

@@ -0,0 +1,60 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1784116681,
+        "narHash": "sha256-uZG9aPDw/etKcm3fxWq/kGLdiZMfoYLwL1xXXvlZKOM=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "2b0cc8dd9c2187ee301fd39bd52dfbf418d01180",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "release-26.05",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,36 @@
+{
+  inputs = {
+    nixpkgs.url = "nixpkgs/release-26.05";
+    utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    utils,
+  }:
+    utils.lib.eachDefaultSystem (system: let
+      pkgs = import nixpkgs {
+        inherit system;
+      };
+      phpPackages = pkgs.phpPackages;
+      phpPackage = pkgs.php.buildEnv {
+        extensions = {
+          enabled,
+          all,
+        }:
+          enabled
+          ++ (with all; [
+            xmlwriter
+          ]);
+      };
+    in {
+      devShells.default = pkgs.mkShell {
+        nativeBuildInputs = [
+          phpPackage
+          phpPackages.composer
+          (phpPackages.box.override {php82 = phpPackage;})
+        ];
+      };
+    });
+}