From 5b7678f309febfb6581566c902e077c679c76116 Mon Sep 17 00:00:00 2001
From: Michiel Borkent <michielborkent@gmail.com>
Date: Sat, 19 Apr 2025 12:12:56 +0200
Subject: [PATCH] Fix virtual thread builder interop (#1810)

---
 CHANGELOG.md                   | 4 ++++
 src/babashka/impl/classes.clj  | 4 +++-
 test/babashka/interop_test.clj | 5 ++++-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 29c6f6e9..62c1c627 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ A preview of the next release can be installed from
 
 [Babashka](https://github.com/babashka/babashka): Native, fast starting Clojure interpreter for scripting
 
+## Unreleased
+
+- Fix virtual `ThreadBuilder` interop
+
 ## 1.12.199 (2025-04-18)
 
 - [#1806](https://github.com/babashka/babashka/issues/1806): Add `cheshire.factory` namespace ([@lread](https://github.com/lread))
diff --git a/src/babashka/impl/classes.clj b/src/babashka/impl/classes.clj
index 6b081ee1..4789e11f 100644
--- a/src/babashka/impl/classes.clj
+++ b/src/babashka/impl/classes.clj
@@ -340,6 +340,7 @@
           java.lang.Throwable
           java.lang.ThreadLocal
           java.lang.Thread$UncaughtExceptionHandler
+          java.lang.Thread$Builder
           java.lang.UnsupportedOperationException
           java.lang.ref.WeakReference
           java.lang.ref.ReferenceQueue
@@ -808,7 +809,8 @@
                                    (instance? org.jsoup.nodes.Element v)
                                    org.jsoup.nodes.Element
                                    ;; keep commas for merge friendliness
-                                   )]
+                                   (instance? java.lang.Thread$Builder v)
+                                   java.lang.Thread$Builder)]
                      ;; (prn :res res)
                      res)))
         m (assoc m (list 'quote 'clojure.lang.Var) 'sci.lang.Var)
diff --git a/test/babashka/interop_test.clj b/test/babashka/interop_test.clj
index de43acb6..570da854 100644
--- a/test/babashka/interop_test.clj
+++ b/test/babashka/interop_test.clj
@@ -18,7 +18,10 @@
          (bb nil (pr-str '(do
                             (def t (Thread. (fn [])))
                             (def vt (Thread/startVirtualThread (fn [])))
-                            [(.isVirtual t) (.isVirtual vt)]))))))
+                            [(.isVirtual t) (.isVirtual vt)])))))
+  (is (bb nil (pr-str '(instance?
+                        java.util.concurrent.Executor
+                        (java.util.concurrent.Executors/newThreadPerTaskExecutor (-> (Thread/ofVirtual) (.name "fusebox-thread-" 1) (.factory))))))))
 
 (deftest domain-sockets-test
   (is (= :success (bb nil (slurp "test-resources/domain_sockets.bb")))))