Fix variable names in rescue blocks

lib/ddtrace/workers.rb

@@ -43,7 +43,7 @@ def callback_traces
           # ensures that the thread will not die because of an exception.
           # TODO[manu]: findout the reason and reschedule the send if it's not
           # a fatal exception
-          Datadog::Tracer.log.error("Error during traces flush: dropped #{items.length} items. Cause: #{e}")
+          Datadog::Tracer.log.error("Error during traces flush: dropped #{traces.length} items. Cause: #{e}")
         end
       end
 
@@ -58,7 +58,7 @@ def callback_services
           # ensures that the thread will not die because of an exception.
           # TODO[manu]: findout the reason and reschedule the send if it's not
           # a fatal exception
-          Datadog::Tracer.log.error("Error during services flush: dropped #{items.length} items. Cause: #{e}")
+          Datadog::Tracer.log.error("Error during services flush: dropped #{services.length} items. Cause: #{e}")
         end
       end
 

spec/ddtrace/workers_spec.rb

@@ -0,0 +1,23 @@
+require 'spec_helper'
+
+RSpec.describe Datadog::Workers::AsyncTransport do
+  describe 'callbacks' do
+    describe 'when raising errors' do
+      it 'does not re-raise' do
+        buf = StringIO.new
+        Datadog::Tracer.log = Datadog::Logger.new(buf)
+        task = proc { raise StandardError }
+        worker = Datadog::Workers::AsyncTransport.new(nil, 100, task, task, 0.5)
+
+        worker.enqueue_trace(get_test_traces(1))
+        worker.enqueue_service(get_test_services)
+
+        expect { worker.callback_traces }.to_not raise_error
+        expect { worker.callback_services }.to_not raise_error
+
+        lines = buf.string.lines
+        expect(lines.count).to eq 2
+      end
+    end
+  end
+end