diff --git a/subprojects/nix-eval-jobs/src/nix-eval-jobs.cc b/subprojects/nix-eval-jobs/src/nix-eval-jobs.cc
index f030c7515..d7a2f1448 100644
--- a/subprojects/nix-eval-jobs/src/nix-eval-jobs.cc
+++ b/subprojects/nix-eval-jobs/src/nix-eval-jobs.cc
@@ -44,9 +44,8 @@
 
 using namespace nix;
 
-using Processor = std::function<void(
-    ref<nix::eval_cache::CachingEvaluator> state, Bindings &autoArgs,
-    AutoCloseFD &to, AutoCloseFD &from, MyArgs &args, AsyncIoRoot &aio)>;
+using Processor =
+    std::function<void(AutoCloseFD &to, AutoCloseFD &from, MyArgs &args)>;
 
 /* Auto-cleanup of fork's process and fds. */
 struct Proc {
@@ -63,30 +62,7 @@ struct Proc {
              from{
                  std::make_shared<AutoCloseFD>(std::move(toPipe.readSide))}]() {
                 debug("created worker process %d", getpid());
-                try {
-                    AsyncIoRoot aio;
-                    auto evalStore = aio.blockOn(myArgs.evalStoreUrl
-                                         ? openStore(*myArgs.evalStoreUrl)
-                                         : openStore());
-                    auto evaluator =
-                        nix::make_ref<nix::eval_cache::CachingEvaluator>(
-                            aio, myArgs.searchPath, evalStore);
-                    Bindings &autoArgs = *myArgs.getAutoArgs(*evaluator);
-                    proc(evaluator, autoArgs, *to, *from, myArgs, aio);
-                } catch (Error &e) {
-                    JSON err;
-                    auto msg = e.msg();
-                    err["error"] = nix::filterANSIEscapes(msg, true);
-                    printError("%1%", Uncolored(msg));
-                    if (tryWriteLine(to->get(), err.dump()) < 0) {
-                        return; // main process died
-                    };
-                    // Don't forget to print it into the STDERR log, this is
-                    // what's shown in the Hydra UI.
-                    if (tryWriteLine(to->get(), "restart") < 0) {
-                        return; // main process died
-                    }
-                }
+                proc(*to, *from, myArgs);
             },
             ProcessOptions{});
 
diff --git a/subprojects/nix-eval-jobs/src/worker.cc b/subprojects/nix-eval-jobs/src/worker.cc
index 07588ae05..b644a0bbe 100644
--- a/subprojects/nix-eval-jobs/src/worker.cc
+++ b/subprojects/nix-eval-jobs/src/worker.cc
@@ -122,9 +122,17 @@ readConstituents(const nix::Value *v, nix::box_ptr<nix::EvalState> &state,
     return std::nullopt;
 }
 
-void worker(nix::ref<nix::eval_cache::CachingEvaluator> evaluator,
-            nix::Bindings &autoArgs, nix::AutoCloseFD &to,
-            nix::AutoCloseFD &from, MyArgs &args, nix::AsyncIoRoot &aio) {
+void worker(nix::AutoCloseFD &to, nix::AutoCloseFD &from, MyArgs &args)
+try {
+    nix::AsyncIoRoot aio;
+
+    auto evalStore = aio.blockOn(args.evalStoreUrl
+                         ? nix::openStore(*args.evalStoreUrl)
+                         : nix::openStore());
+    auto evaluator =
+        nix::make_ref<nix::eval_cache::CachingEvaluator>(
+            aio, args.searchPath, evalStore);
+    nix::Bindings &autoArgs = *args.getAutoArgs(*evaluator);
 
     nix::Value vRoot = [&]() {
         auto state = evaluator->begin(aio);
@@ -253,4 +261,17 @@ void worker(nix::ref<nix::eval_cache::CachingEvaluator> evaluator,
     if (tryWriteLine(to.get(), "restart") < 0) {
         return; // main process died
     };
+} catch (nix::Error &e) {
+    nix::JSON err;
+    auto msg = e.msg();
+    err["error"] = nix::filterANSIEscapes(msg, true);
+    printError("%1%", nix::Uncolored(msg));
+    if (tryWriteLine(to.get(), err.dump()) < 0) {
+        return; // main process died
+    };
+    // Don't forget to print it into the STDERR log, this is
+    // what's shown in the Hydra UI.
+    if (tryWriteLine(to.get(), "restart") < 0) {
+        return; // main process died
+    }
 }
diff --git a/subprojects/nix-eval-jobs/src/worker.hh b/subprojects/nix-eval-jobs/src/worker.hh
index d4c41caff..21e8768c9 100644
--- a/subprojects/nix-eval-jobs/src/worker.hh
+++ b/subprojects/nix-eval-jobs/src/worker.hh
@@ -15,6 +15,4 @@ class EvalState;
 template <typename T> class ref;
 } // namespace nix
 
-void worker(nix::ref<nix::eval_cache::CachingEvaluator> evaluator,
-            nix::Bindings &autoArgs, nix::AutoCloseFD &to,
-            nix::AutoCloseFD &from, MyArgs &args, nix::AsyncIoRoot &aio);
+void worker(nix::AutoCloseFD &to, nix::AutoCloseFD &from, MyArgs &args);