Add checks to ensure that ignore_exceptions is properly configured

lib/resque/plugins/retry.rb

@@ -43,13 +43,30 @@ module Retry
       # @api public
       class AmbiguousRetryStrategyException < StandardError; end
 
+      # Raised if there is a problem with the configuration of resque-retry.
+      #
+      # @api public
+      class RetryConfigurationException < StandardError; end
+
       # Fail fast, when extended, if the "receiver" is misconfigured
       #
       # @api private
       def self.extended(receiver)
         if receiver.instance_variable_get('@fatal_exceptions') && receiver.instance_variable_get('@retry_exceptions')
           raise AmbiguousRetryStrategyException.new(%{You can't define both "@fatal_exceptions" and "@retry_exceptions"})
         end
+
+        # Check that ignore_exceptions is a subset of retry_exceptions
+        retry_exceptions = receiver.instance_variable_get('@retry_exceptions')
+        if retry_exceptions.is_a?(Hash)
+          exceptions = retry_exceptions.keys
+        else
+          exceptions = Array(retry_exceptions)
+        end
+        excess_exceptions = Array(receiver.instance_variable_get('@ignore_exceptions')) - exceptions
+        unless excess_exceptions.empty?
+          raise RetryConfigurationException, "The following exceptions are defined in @ignore_exceptions but not in @retry_exceptions: #{excess_exceptions.join(', ')}."
+        end
       end
 
       # Copy retry criteria checks, try again callbacks, and give up callbacks

test/ignore_exceptions_test.rb

@@ -23,4 +23,16 @@ def test_ignore_exceptions
     perform_next_job(@worker)
     assert_equal '1', Resque.redis.get(retry_key), 'retry counter'
   end
+
+  def test_ignore_exception_configuration_1
+    assert_raises Resque::Plugins::Retry::RetryConfigurationException do
+      IgnoreExceptionsImproperlyConfiguredJob1.extend(Resque::Plugins::Retry)
+    end
+  end
+
+  def test_ignore_exception_configuration_2
+    assert_raises Resque::Plugins::Retry::RetryConfigurationException do
+      IgnoreExceptionsImproperlyConfiguredJob2.extend(Resque::Plugins::Retry)
+    end
+  end
 end

test/test_jobs.rb

@@ -591,3 +591,16 @@ def self.perform
     "Hello, World!"
   end
 end
+
+class IgnoreExceptionsImproperlyConfiguredJob1
+  # Manually extend Resque::Plugins::Retry in the test code to catch the
+  # exception.
+  @ignore_exceptions = [CustomException]
+end
+
+class IgnoreExceptionsImproperlyConfiguredJob2
+  # Manually extend Resque::Plugins::Retry in the test code to catch the
+  # exception.
+  @ignore_exceptions = [CustomException]
+  @retry_exceptions = { AnotherCustomException => 0 }
+end