guard against undefined method

Author: AlexanderZagaynov

lib/concurrent/executor/ruby_thread_pool_executor.rb

@@ -300,7 +300,9 @@ def initialize(pool, id: nil)
         @queue  = Queue.new
         @pool   = pool
         @thread = create_worker @queue, pool, pool.idletime
-        @thread.name = [pool.name, 'worker', id].compact.join('-')
+        if Concurrent.on_cruby? && Concurrent.ruby_version(:>=, 2, 3, 0)
+          @thread.name = [pool.name, 'worker', id].compact.join('-')
+        end
       end
 
       def <<(message)

spec/concurrent/executor/ruby_thread_pool_executor_spec.rb

@@ -55,34 +55,36 @@ module Concurrent
       end
     end
 
-    context 'threads naming' do
-      subject do
-        opts = { min_threads: 2 }
-        opts[:name] = pool_name if pool_name
-        described_class.new(opts)
-      end
+    if Concurrent.on_cruby? && Concurrent.ruby_version(:>=, 2, 3, 0)
+      context 'threads naming' do
+        subject do
+          opts = { min_threads: 2 }
+          opts[:name] = pool_name if pool_name
+          described_class.new(opts)
+        end
 
-      let(:names) { Concurrent::Set.new }
+        let(:names) { Concurrent::Set.new }
 
-      before do
-        subject.post(names) { |names| names << Thread.current.name }
-        subject.post(names) { |names| names << Thread.current.name }
-        subject.shutdown
-        subject.wait_for_termination(pool_termination_timeout)
-        expect(names.size).to eq 2
-      end
+        before do
+          subject.post(names) { |names| names << Thread.current.name }
+          subject.post(names) { |names| names << Thread.current.name }
+          subject.shutdown
+          subject.wait_for_termination(pool_termination_timeout)
+          expect(names.size).to eq 2
+        end
 
-      context 'without pool name' do
-        let(:pool_name) { }
-        it 'sets counted name' do
-          expect(names.all? { |name| name =~ /^worker-\d+$/ }).to be true
+        context 'without pool name' do
+          let(:pool_name) { }
+          it 'sets counted name' do
+            expect(names.all? { |name| name =~ /^worker-\d+$/ }).to be true
+          end
         end
-      end
 
-      context 'with pool name' do
-        let(:pool_name) { 'MyExecutor' }
-        it 'sets counted name' do
-          expect(names.all? { |name| name =~ /^MyExecutor-worker-\d+$/ }).to be true
+        context 'with pool name' do
+          let(:pool_name) { 'MyExecutor' }
+          it 'sets counted name' do
+            expect(names.all? { |name| name =~ /^MyExecutor-worker-\d+$/ }).to be true
+          end
         end
       end
     end