Handle cases where job is nil in Que error notifier

This should fix #545

CHANGELOG.md

@@ -1,6 +1,15 @@
 Changelog
 =========
 
+## TBD
+
+### Fixes
+
+* Handle `nil` values for the `job` block parameter for the Que error notifier.
+  This occurs under some conditions such as database connection failures.
+  | [#545](https://github.com/bugsnag/bugsnag-ruby/issues/545)
+  | [#548](https://github.com/bugsnag/bugsnag-ruby/pull/548)
+
 ## 6.11.1 (22 Jan 2019)
 
 ### Fixes

lib/bugsnag/integrations/que.rb

@@ -3,21 +3,23 @@
 if defined?(::Que)
   handler = proc do |error, job|
     begin
-      job = job.dup # Make sure the original job object is not mutated.
+      job &&= job.dup # Make sure the original job object is not mutated.
 
       Bugsnag.notify(error, true) do |report|
-        job[:error_count] += 1
+        if job
+          job[:error_count] += 1
 
-        # If the job was scheduled using ActiveJob then unwrap the job details for clarity:
-        if job[:job_class] == "ActiveJob::QueueAdapters::QueAdapter::JobWrapper"
-          wrapped_job = job[:args].last
-          wrapped_job = wrapped_job.each_with_object({}) { |(k, v), result| result[k.to_sym] = v } # Symbolize keys
+          # If the job was scheduled using ActiveJob then unwrap the job details for clarity:
+          if job[:job_class] == "ActiveJob::QueueAdapters::QueAdapter::JobWrapper"
+            wrapped_job = job[:args].last
+            wrapped_job = wrapped_job.each_with_object({}) { |(k, v), result| result[k.to_sym] = v } # Symbolize keys
 
-          # Align key names with keys in `job`
-          wrapped_job[:queue] = wrapped_job.delete(:queue_name)
-          wrapped_job[:args]  = wrapped_job.delete(:arguments)
+            # Align key names with keys in `job`
+            wrapped_job[:queue] = wrapped_job.delete(:queue_name)
+            wrapped_job[:args]  = wrapped_job.delete(:arguments)
 
-          job.merge!(wrapper_job_class: job[:job_class], wrapper_job_id: job[:job_id]).merge!(wrapped_job)
+            job.merge!(wrapper_job_class: job[:job_class], wrapper_job_id: job[:job_id]).merge!(wrapped_job)
+          end
         end
 
         report.add_tab(:job, job)
@@ -43,4 +45,4 @@
     Bugsnag.configuration.app_type ||= "que"
     Que.error_handler = handler
   end
-end
+end

spec/integrations/que_spec.rb

@@ -6,6 +6,9 @@
     unless defined?(::Que)
       @mocked_que = true
       class ::Que
+        class << self
+          attr_accessor :error_notifier
+        end
       end
       module Kernel
         alias_method :old_require, :require
@@ -31,7 +34,6 @@ def require(path)
     expect(report).to receive(:add_tab).with(:job, {
       :error_count => 1,
       :job_class => 'ActiveJob::QueueAdapters::QueAdapter::JobWrapper',
-      :args => [{"queue_name" => "foo", "arguments" => "bar"}],
       :job_id => "ID",
       :wrapper_job_class => 'ActiveJob::QueueAdapters::QueAdapter::JobWrapper',
       :wrapper_job_id => "ID",
@@ -60,6 +62,24 @@ def require(path)
     load './lib/bugsnag/integrations/que.rb'
   end
 
+  context 'when the job is nil' do
+    it 'notifies Bugsnag' do
+      load './lib/bugsnag/integrations/que.rb'
+      error = RuntimeError.new('nil job')
+      report = Bugsnag::Report.new(error, Bugsnag::Configuration.new)
+      expect(Bugsnag).to receive(:notify).with(error, true).and_yield(report)
+
+      Que.error_notifier.call(error, nil)
+
+      expect(report.meta_data['custom'].fetch('job')).to eq(nil)
+      expect(report.severity).to eq('error')
+      expect(report.severity_reason).to eq({
+        :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+        :attributes => {:framework => 'Que'},
+      })
+    end
+  end
+
   after do
     Object.send(:remove_const, :Que) if @mocked_que
     module Kernel