feat: initial v3 rewrite

lib/impl/jobPatched.nix

@@ -0,0 +1,43 @@
+{
+  lib,
+  helpers,
+}: let
+  inherit (lib) toList optionalAttrs optional;
+  inherit (helpers) prependToBeforeScript appendToAfterScript filterJobVariables;
+in
+  {
+    key,
+    job,
+    pipelineName,
+    nixConfig,
+  }:
+    job
+    // (optionalAttrs nixConfig.enable (
+      (prependToBeforeScript ["source setup_nix_ci \"gitlab-ci:pipeline:${pipelineName}:job-deps:${key}\""] job)
+      // (appendToAfterScript ["finalize_nix_ci"] job)
+    ))
+    // optionalAttrs nixConfig.enable (
+      (let
+        variables =
+          (filterJobVariables false job)
+          // optionalAttrs nixConfig.enableRunnerCache {
+            NIX_CI_CACHE_STRATEGY = "runner";
+          };
+      in
+        # filter empty variables
+        optionalAttrs (variables != {}) {
+          inherit variables;
+        })
+      // (let
+        cache =
+          (toList (job.cache or []))
+          ++ (optional nixConfig.enableRunnerCache {
+            key = nixConfig.runnerCacheKey;
+            paths = [".nix-cache/"];
+          });
+      in
+        # filter empty cache
+        optionalAttrs (cache != []) {
+          inherit cache;
+        })
+    )