Abort when exception is raised during analysis

Fixes an issue where Java exceptions did not propogate up in Thread#join and
could result in issues getting dropped.

See related issue for more information: jruby/jruby#2354

Dockerfile

@@ -29,4 +29,6 @@ USER app
 
 ENV JAVA_OPTS="-XX:+UseParNewGC -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10"
 
+ENV JAVA_OPTS="-XX:+UseParNewGC -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10
+
 CMD ["/usr/src/app/bin/duplication"]

lib/cc/engine/analyzers/file_thread_pool.rb

@@ -16,8 +16,8 @@ def run(&block)
           queue = build_queue
           lock = Mutex.new
 
-          @workers = thread_count.times.map do
-            Thread.new do
+          @workers = Array.new(thread_count) do
+            with_thread_abortion do
               while (item = next_item(queue, lock))
                 yield item
               end
@@ -54,6 +54,13 @@ def thread_count
             DEFAULT_CONCURRENCY
           end
         end
+
+        def with_thread_abortion
+          t = Thread.new do
+            yield
+          end
+          (t.abort_on_exception = true) && t
+        end
       end
     end
   end

spec/cc/engine/analyzers/file_thread_pool_spec.rb

@@ -3,8 +3,9 @@
 
 RSpec.describe CC::Engine::Analyzers::FileThreadPool do
   describe "#run" do
+    let(:thread) { Thread.new {} }
     it "uses default count of threads when concurrency is not specified" do
-      allow(Thread).to receive(:new)
+      allow(Thread).to receive(:new).and_return(thread)
 
       pool = CC::Engine::Analyzers::FileThreadPool.new([])
       pool.run  {}
@@ -15,7 +16,7 @@
     end
 
     it "uses default concurrency when concurrency is over max" do
-      allow(Thread).to receive(:new)
+      allow(Thread).to receive(:new).and_return(thread)
 
       run_pool_with_concurrency(
         CC::Engine::Analyzers::FileThreadPool::DEFAULT_CONCURRENCY + 2
@@ -27,7 +28,7 @@
     end
 
     it "uses default concucurrency when concucurrency is under 1" do
-      allow(Thread).to receive(:new)
+      allow(Thread).to receive(:new).and_return(thread)
 
       run_pool_with_concurrency(-2)
 
@@ -37,7 +38,7 @@
     end
 
     it "uses supplied concurrency when valid" do
-      allow(Thread).to receive(:new)
+      allow(Thread).to receive(:new).and_return(thread)
 
       run_pool_with_concurrency(1)
 
@@ -57,6 +58,14 @@
       expect(results).to include("321")
       expect(results).to include("zyx")
     end
+
+    it "aborts on a thread exception" do
+      allow(Thread).to receive(:new).and_return(thread)
+
+      run_pool_with_concurrency(1)
+
+      expect(thread.abort_on_exception).to eq(true)
+    end
   end
 
   def run_pool_with_concurrency(concurrency)