The arguments of Thread.new need to be marked as shared between multi…

…ple threads

* See #3179 (comment)

CHANGELOG.md

@@ -13,6 +13,7 @@ Bug fixes:
 * Fix some C API functions which were failing when called with Ruby values represented as Java primitives (#3352, @eregon).
 * Fix `IO.select([io], nil, [io])` on macOS, it was hanging due to a bug in macOS `poll(2)` (#3346, @eregon, @andrykonchin).
 * Run context cleanup such as showing the output of tools when `SignalException` and `Interrupt` escape (@eregon).
+* The arguments of `Thread.new(*args, &block)` need to be marked as shared between multiple threads (#3179, @eregon).
 
 Compatibility:
 

spec/truffle/thread_safe_objects_spec.rb

@@ -293,6 +293,35 @@ def wb; @wb; end
     shared?(new_hash).should == true
   end
 
+  describe "Thread.new's" do
+    it "block" do
+      obj = Object.new
+      t = Thread.new { sleep }
+      begin
+        shared?(obj).should == true
+      ensure
+        t.kill
+        t.join
+      end
+    end
+
+    # avoid capturing local variables in the spec example below
+    thread_body = proc { sleep }
+
+    it "arguments" do
+      obj1 = Object.new
+      obj2 = Object.new
+      t = Thread.new(obj1, obj2, &thread_body)
+      begin
+        shared?(obj1).should == true
+        shared?(obj2).should == true
+      ensure
+        t.kill
+        t.join
+      end
+    end
+  end
+
   it "Fiber local variables which share the value (since they can be accessed from other threads)" do
     require 'fiber'
     # Create a new Thread to make sure the root Fiber is shared as expected

src/main/java/org/truffleruby/core/thread/ThreadNodes.java

@@ -433,7 +433,7 @@ private Object init(RubyThread thread, RubyProc block, ArgumentsDescriptor descr
 
             if (getLanguage().options.SHARED_OBJECTS_ENABLED) {
                 getContext().getThreadManager().startSharing(thread, sharingReason);
-                SharedObjects.shareDeclarationFrame(getLanguage(), block, info);
+                SharedObjects.shareBlockAndArguments(getLanguage(), block, args, info);
             }
 
             getContext().getThreadManager().initialize(

src/main/java/org/truffleruby/language/objects/shared/SharedObjects.java

@@ -82,13 +82,14 @@ private static void shareContextRoots(RubyLanguage language, RubyContext context
         }
     }
 
-    public static void shareDeclarationFrame(RubyLanguage language, RubyProc block, String info) {
+    public static void shareBlockAndArguments(RubyLanguage language, RubyProc block, Object[] args, String info) {
         if (language.options.SHARED_OBJECTS_DEBUG) {
-            RubyLanguage.LOGGER.info("sharing decl frame of " + info);
+            RubyLanguage.LOGGER.info("sharing block and arguments of " + info);
         }
 
         final Set<Object> objects = ObjectGraph.newObjectSet();
         ObjectGraph.getObjectsInFrame(block.declarationFrame, objects);
+        ObjectGraph.addProperty(objects, args);
 
         final Deque<Object> stack = new ArrayDeque<>(objects);
         shareObjects(stack);