Fix RUBY-2805 Push monitor thread can exit when address resolution fails

lib/mongo/server/push_monitor.rb

@@ -110,7 +110,7 @@ def do_work
         if new_description.topology_version
           @topology_version = new_description.topology_version
         end
-      rescue Mongo::Error => exc
+      rescue IOError, SocketError, SystemCallError, Mongo::Error => exc
         stop_requested = @lock.synchronize { @stop_requested }
         if stop_requested
           # Ignore the exception, see RUBY-2771.

spec/mongo/server/monitor/connection_spec.rb

@@ -136,6 +136,28 @@
     end
   end
 
+  describe '#connect!' do
+
+    let(:options) do
+      SpecConfig.instance.test_options.merge(
+        app_metadata: monitor_app_metadata,
+      )
+    end
+
+    context 'when address resolution fails' do
+      let(:connection) { described_class.new(server.address, options) }
+
+      it 'propagates the exception' do
+        connection
+
+        expect(Socket).to receive(:getaddrinfo).and_raise(SocketError.new('Test exception'))
+        lambda do
+          connection.connect!
+        end.should raise_error(SocketError, 'Test exception')
+      end
+    end
+  end
+
   describe '#check_document' do
     context 'with API version' do
       let(:meta) do

spec/mongo/server/push_monitor_spec.rb

@@ -0,0 +1,82 @@
+# frozen_string_literal: true
+# encoding: utf-8
+
+require 'spec_helper'
+
+describe Mongo::Server::PushMonitor do
+  before(:all) do
+    ClientRegistry.instance.close_all_clients
+  end
+
+  let(:address) do
+    default_address
+  end
+
+  let(:listeners) do
+    Mongo::Event::Listeners.new
+  end
+
+  let(:monitor_options) do
+    {}
+  end
+
+  let(:monitor_app_metadata) do
+    Mongo::Server::Monitor::AppMetadata.new(
+      server_api: SpecConfig.instance.ruby_options[:server_api],
+    )
+  end
+
+  let(:cluster) do
+    double('cluster').tap do |cluster|
+      allow(cluster).to receive(:run_sdam_flow)
+      allow(cluster).to receive(:heartbeat_interval).and_return(1000)
+    end
+  end
+
+  let(:server) do
+    Mongo::Server.new(address, cluster, Mongo::Monitoring.new, listeners,
+      monitoring_io: false)
+  end
+
+  let(:monitor) do
+    register_background_thread_object(
+      Mongo::Server::Monitor.new(server, listeners, Mongo::Monitoring.new,
+        SpecConfig.instance.test_options.merge(cluster: cluster).merge(monitor_options).update(
+          app_metadata: monitor_app_metadata,
+          push_monitor_app_metadata: monitor_app_metadata))
+    )
+  end
+
+  let(:topology_version) do
+    Mongo::TopologyVersion.new('processId' => BSON::ObjectId.new, 'counter' => 1)
+  end
+
+  let(:check_document) do
+    {hello: 1}
+  end
+
+  let(:push_monitor) do
+    described_class.new(monitor, topology_version, monitor.monitoring,
+      **monitor.options.merge(check_document: check_document))
+  end
+
+  describe '#do_work' do
+    it 'works' do
+      lambda do
+        push_monitor.do_work
+      end.should_not raise_error
+    end
+
+    context 'network error during check' do
+      it 'does not propagate the exception' do
+        push_monitor
+
+        expect(Socket).to receive(:getaddrinfo).and_raise(SocketError.new('Test exception'))
+        lambda do
+          push_monitor.do_work
+        end.should_not raise_error
+      end
+    end
+  end
+
+end