Merge branch 'master' into update_default_hsts_max_age

30 files changed, 570 insertions, 30 deletions

diff --git a/activejob/CHANGELOG.md b/activejob/CHANGELOG.md
index 4453f845f4..c6a3ad8ade 100644
--- a/activejob/CHANGELOG.md
+++ b/activejob/CHANGELOG.md
@@ -1,12 +1,20 @@
-## Rails 5.2.0.beta2 (November 28, 2017) ##
+## Rails 6.0.0.alpha (Unreleased) ##
 
-*   No changes.
+*   Add support for timezones to Active Job
 
+    Record what was the current timezone in effect when the job was
+    enqueued and then restore when the job is executed in same way
+    that the current locale is recorded and restored.
 
-## Rails 5.2.0.beta1 (November 27, 2017) ##
+    *Andrew White*
 
-*   Support redis-rb 4.0.
+*   Rails 6 requires Ruby 2.4.1 or newer.
 
     *Jeremy Daer*
 
-Please check [5-1-stable](https://github.com/rails/rails/blob/5-1-stable/activejob/CHANGELOG.md) for previous changes.
+*   Add support to define custom argument serializers.
+
+    *Evgenii Pecherkin*, *Rafael Mendonça França*
+
+
+Please check [5-2-stable](https://github.com/rails/rails/blob/5-2-stable/activejob/CHANGELOG.md) for previous changes.
diff --git a/activejob/activejob.gemspec b/activejob/activejob.gemspec
index 71e32f695b..be6292f737 100644
--- a/activejob/activejob.gemspec
+++ b/activejob/activejob.gemspec
@@ -9,7 +9,7 @@ Gem::Specification.new do |s|
   s.summary     = "Job framework with pluggable queues."
   s.description = "Declare job classes that can be run by a variety of queueing backends."
 
-  s.required_ruby_version = ">= 2.2.2"
+  s.required_ruby_version = ">= 2.4.1"
 
   s.license = "MIT"
 
diff --git a/activejob/lib/active_job.rb b/activejob/lib/active_job.rb
index 626abaa767..01fab4d918 100644
--- a/activejob/lib/active_job.rb
+++ b/activejob/lib/active_job.rb
@@ -33,6 +33,7 @@ module ActiveJob
 
   autoload :Base
   autoload :QueueAdapters
+  autoload :Serializers
   autoload :ConfiguredJob
   autoload :TestCase
   autoload :TestHelper
diff --git a/activejob/lib/active_job/arguments.rb b/activejob/lib/active_job/arguments.rb
index de11e7fcb1..86bb0c5540 100644
--- a/activejob/lib/active_job/arguments.rb
+++ b/activejob/lib/active_job/arguments.rb
@@ -14,8 +14,8 @@ module ActiveJob
   end
 
   # Raised when an unsupported argument type is set as a job argument. We
-  # currently support NilClass, Integer, Fixnum, Float, String, TrueClass, FalseClass,
-  # Bignum, BigDecimal, and objects that can be represented as GlobalIDs (ex: Active Record).
+  # currently support NilClass, Integer, Float, String, TrueClass, FalseClass,
+  # BigDecimal, and objects that can be represented as GlobalIDs (ex: Active Record).
   # Raised if you set the key for a Hash something else than a string or
   # a symbol. Also raised when trying to serialize an object which can't be
   # identified with a Global ID - such as an unpersisted Active Record model.
@@ -25,7 +25,6 @@ module ActiveJob
     extend self
     # :nodoc:
     TYPE_WHITELIST = [ NilClass, String, Integer, Float, BigDecimal, TrueClass, FalseClass ]
-    TYPE_WHITELIST.push(Fixnum, Bignum) unless 1.class == Integer
 
     # Serializes a set of arguments. Whitelisted types are returned
     # as-is. Arrays/Hashes are serialized element by element.
@@ -44,13 +43,24 @@ module ActiveJob
     end
 
     private
+
       # :nodoc:
       GLOBALID_KEY = "_aj_globalid".freeze
       # :nodoc:
       SYMBOL_KEYS_KEY = "_aj_symbol_keys".freeze
       # :nodoc:
       WITH_INDIFFERENT_ACCESS_KEY = "_aj_hash_with_indifferent_access".freeze
-      private_constant :GLOBALID_KEY, :SYMBOL_KEYS_KEY, :WITH_INDIFFERENT_ACCESS_KEY
+      # :nodoc:
+      OBJECT_SERIALIZER_KEY = "_aj_serialized"
+
+      # :nodoc:
+      RESERVED_KEYS = [
+        GLOBALID_KEY, GLOBALID_KEY.to_sym,
+        SYMBOL_KEYS_KEY, SYMBOL_KEYS_KEY.to_sym,
+        OBJECT_SERIALIZER_KEY, OBJECT_SERIALIZER_KEY.to_sym,
+        WITH_INDIFFERENT_ACCESS_KEY, WITH_INDIFFERENT_ACCESS_KEY.to_sym,
+      ]
+      private_constant :RESERVED_KEYS
 
       def serialize_argument(argument)
         case argument
@@ -70,7 +80,7 @@ module ActiveJob
           result[SYMBOL_KEYS_KEY] = symbol_keys
           result
         else
-          raise SerializationError.new("Unsupported argument type: #{argument.class.name}")
+          Serializers.serialize(argument)
         end
       end
 
@@ -85,6 +95,8 @@ module ActiveJob
         when Hash
           if serialized_global_id?(argument)
             deserialize_global_id argument
+          elsif custom_serialized?(argument)
+            Serializers.deserialize(argument)
           else
             deserialize_hash(argument)
           end
@@ -101,6 +113,10 @@ module ActiveJob
         GlobalID::Locator.locate hash[GLOBALID_KEY]
       end
 
+      def custom_serialized?(hash)
+        hash.key?(OBJECT_SERIALIZER_KEY)
+      end
+
       def serialize_hash(argument)
         argument.each_with_object({}) do |(key, value), hash|
           hash[serialize_hash_key(key)] = serialize_argument(value)
@@ -117,14 +133,6 @@ module ActiveJob
         result
       end
 
-      # :nodoc:
-      RESERVED_KEYS = [
-        GLOBALID_KEY, GLOBALID_KEY.to_sym,
-        SYMBOL_KEYS_KEY, SYMBOL_KEYS_KEY.to_sym,
-        WITH_INDIFFERENT_ACCESS_KEY, WITH_INDIFFERENT_ACCESS_KEY.to_sym,
-      ]
-      private_constant :RESERVED_KEYS
-
       def serialize_hash_key(key)
         case key
         when *RESERVED_KEYS
diff --git a/activejob/lib/active_job/base.rb b/activejob/lib/active_job/base.rb
index ae112abb2c..2b2a59e969 100644
--- a/activejob/lib/active_job/base.rb
+++ b/activejob/lib/active_job/base.rb
@@ -9,6 +9,7 @@ require "active_job/execution"
 require "active_job/callbacks"
 require "active_job/exceptions"
 require "active_job/logging"
+require "active_job/timezones"
 require "active_job/translation"
 
 module ActiveJob #:nodoc:
@@ -59,6 +60,7 @@ module ActiveJob #:nodoc:
   # * SerializationError - Error class for serialization errors.
   class Base
     include Core
+    include Serializers
     include QueueAdapter
     include QueueName
     include QueuePriority
@@ -67,6 +69,7 @@ module ActiveJob #:nodoc:
     include Callbacks
     include Exceptions
     include Logging
+    include Timezones
     include Translation
 
     ActiveSupport.run_load_hooks(:active_job, self)
diff --git a/activejob/lib/active_job/core.rb b/activejob/lib/active_job/core.rb
index 879746fc01..da841ae45b 100644
--- a/activejob/lib/active_job/core.rb
+++ b/activejob/lib/active_job/core.rb
@@ -31,6 +31,9 @@ module ActiveJob
 
       # I18n.locale to be used during the job.
       attr_accessor :locale
+
+      # Timezone to be used during the job.
+      attr_accessor :timezone
     end
 
     # These methods will be included into any Active Job object, adding
@@ -87,7 +90,8 @@ module ActiveJob
         "priority"   => priority,
         "arguments"  => serialize_arguments(arguments),
         "executions" => executions,
-        "locale"     => I18n.locale.to_s
+        "locale"     => I18n.locale.to_s,
+        "timezone"   => Time.zone.try(:name)
       }
     end
 
@@ -125,6 +129,7 @@ module ActiveJob
       self.serialized_arguments = job_data["arguments"]
       self.executions           = job_data["executions"]
       self.locale               = job_data["locale"] || I18n.locale.to_s
+      self.timezone             = job_data["timezone"] || Time.zone.try(:name)
     end
 
     private
diff --git a/activejob/lib/active_job/exceptions.rb b/activejob/lib/active_job/exceptions.rb
index 8b4a88ba6a..ae700848d0 100644
--- a/activejob/lib/active_job/exceptions.rb
+++ b/activejob/lib/active_job/exceptions.rb
@@ -61,18 +61,28 @@ module ActiveJob
       # Discard the job with no attempts to retry, if the exception is raised. This is useful when the subject of the job,
       # like an Active Record, is no longer available, and the job is thus no longer relevant.
       #
+      # You can also pass a block that'll be invoked. This block is yielded with the job instance as the first and the error instance as the second parameter.
+      #
       # ==== Example
       #
       #  class SearchIndexingJob < ActiveJob::Base
       #    discard_on ActiveJob::DeserializationError
+      #    discard_on(CustomAppException) do |job, exception|
+      #      ExceptionNotifier.caught(exception)
+      #    end
       #
       #    def perform(record)
       #      # Will raise ActiveJob::DeserializationError if the record can't be deserialized
+      #      # Might raise CustomAppException for something domain specific
       #    end
       #  end
       def discard_on(exception)
         rescue_from exception do |error|
-          logger.error "Discarded #{self.class} due to a #{exception}. The original exception was #{error.cause.inspect}."
+          if block_given?
+            yield self, exception
+          else
+            logger.error "Discarded #{self.class} due to a #{exception}. The original exception was #{error.cause.inspect}."
+          end
         end
       end
     end
diff --git a/activejob/lib/active_job/gem_version.rb b/activejob/lib/active_job/gem_version.rb
index 49dfd4095e..770f70dc5e 100644
--- a/activejob/lib/active_job/gem_version.rb
+++ b/activejob/lib/active_job/gem_version.rb
@@ -7,10 +7,10 @@ module ActiveJob
   end
 
   module VERSION
-    MAJOR = 5
-    MINOR = 2
+    MAJOR = 6
+    MINOR = 0
     TINY  = 0
-    PRE   = "beta2"
+    PRE   = "alpha"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
   end
diff --git a/activejob/lib/active_job/logging.rb b/activejob/lib/active_job/logging.rb
index f53b7eaee5..3312857ac7 100644
--- a/activejob/lib/active_job/logging.rb
+++ b/activejob/lib/active_job/logging.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require "active_support/core_ext/hash/transform_values"
 require "active_support/core_ext/string/filters"
 require "active_support/tagged_logging"
 require "active_support/logger"
@@ -12,13 +11,13 @@ module ActiveJob
     included do
       cattr_accessor :logger, default: ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDOUT))
 
-      around_enqueue do |_, block, _|
+      around_enqueue do |_, block|
         tag_logger do
           block.call
         end
       end
 
-      around_perform do |job, block, _|
+      around_perform do |job, block|
         tag_logger(job.class.name, job.job_id) do
           payload = { adapter: job.class.queue_adapter, job: job }
           ActiveSupport::Notifications.instrument("perform_start.active_job", payload.dup)
diff --git a/activejob/lib/active_job/railtie.rb b/activejob/lib/active_job/railtie.rb
index 7b0742a6d2..d0294854d3 100644
--- a/activejob/lib/active_job/railtie.rb
+++ b/activejob/lib/active_job/railtie.rb
@@ -7,17 +7,28 @@ module ActiveJob
   # = Active Job Railtie
   class Railtie < Rails::Railtie # :nodoc:
     config.active_job = ActiveSupport::OrderedOptions.new
+    config.active_job.custom_serializers = []
 
     initializer "active_job.logger" do
       ActiveSupport.on_load(:active_job) { self.logger = ::Rails.logger }
     end
 
+    initializer "active_job.custom_serializers" do |app|
+      config.after_initialize do
+        custom_serializers = app.config.active_job.delete(:custom_serializers)
+        ActiveJob::Serializers.add_serializers custom_serializers
+      end
+    end
+
     initializer "active_job.set_configs" do |app|
       options = app.config.active_job
       options.queue_adapter ||= :async
 
       ActiveSupport.on_load(:active_job) do
-        options.each { |k, v| send("#{k}=", v) }
+        options.each do  |k, v|
+          k = "#{k}="
+          send(k, v) if respond_to? k
+        end
       end
     end
 
diff --git a/activejob/lib/active_job/serializers.rb b/activejob/lib/active_job/serializers.rb
new file mode 100644
index 0000000000..df66e66659
--- /dev/null
+++ b/activejob/lib/active_job/serializers.rb
@@ -0,0 +1,64 @@
+# frozen_string_literal: true
+
+require "set"
+
+module ActiveJob
+  # The <tt>ActiveJob::Serializers</tt> module is used to store a list of known serializers
+  # and to add new ones. It also has helpers to serialize/deserialize objects.
+  module Serializers # :nodoc:
+    extend ActiveSupport::Autoload
+    extend ActiveSupport::Concern
+
+    autoload :ObjectSerializer
+    autoload :SymbolSerializer
+    autoload :DurationSerializer
+    autoload :DateTimeSerializer
+    autoload :DateSerializer
+    autoload :TimeWithZoneSerializer
+    autoload :TimeSerializer
+
+    mattr_accessor :_additional_serializers
+    self._additional_serializers = Set.new
+
+    class << self
+      # Returns serialized representative of the passed object.
+      # Will look up through all known serializers.
+      # Raises <tt>ActiveJob::SerializationError</tt> if it can't find a proper serializer.
+      def serialize(argument)
+        serializer = serializers.detect { |s| s.serialize?(argument) }
+        raise SerializationError.new("Unsupported argument type: #{argument.class.name}") unless serializer
+        serializer.serialize(argument)
+      end
+
+      # Returns deserialized object.
+      # Will look up through all known serializers.
+      # If no serializer found will raise <tt>ArgumentError</tt>.
+      def deserialize(argument)
+        serializer_name = argument[Arguments::OBJECT_SERIALIZER_KEY]
+        raise ArgumentError, "Serializer name is not present in the argument: #{argument.inspect}" unless serializer_name
+
+        serializer = serializer_name.safe_constantize
+        raise ArgumentError, "Serializer #{serializer_name} is not known" unless serializer
+
+        serializer.deserialize(argument)
+      end
+
+      # Returns list of known serializers.
+      def serializers
+        self._additional_serializers
+      end
+
+      # Adds new serializers to a list of known serializers.
+      def add_serializers(*new_serializers)
+        self._additional_serializers += new_serializers.flatten
+      end
+    end
+
+    add_serializers SymbolSerializer,
+      DurationSerializer,
+      DateTimeSerializer,
+      DateSerializer,
+      TimeWithZoneSerializer,
+      TimeSerializer
+  end
+end
diff --git a/activejob/lib/active_job/serializers/date_serializer.rb b/activejob/lib/active_job/serializers/date_serializer.rb
new file mode 100644
index 0000000000..e995d30faa
--- /dev/null
+++ b/activejob/lib/active_job/serializers/date_serializer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Serializers
+    class DateSerializer < ObjectSerializer # :nodoc:
+      def serialize(date)
+        super("value" => date.iso8601)
+      end
+
+      def deserialize(hash)
+        Date.iso8601(hash["value"])
+      end
+
+      private
+
+        def klass
+          Date
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/serializers/date_time_serializer.rb b/activejob/lib/active_job/serializers/date_time_serializer.rb
new file mode 100644
index 0000000000..fe780a1978
--- /dev/null
+++ b/activejob/lib/active_job/serializers/date_time_serializer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Serializers
+    class DateTimeSerializer < ObjectSerializer # :nodoc:
+      def serialize(time)
+        super("value" => time.iso8601)
+      end
+
+      def deserialize(hash)
+        DateTime.iso8601(hash["value"])
+      end
+
+      private
+
+        def klass
+          DateTime
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/serializers/duration_serializer.rb b/activejob/lib/active_job/serializers/duration_serializer.rb
new file mode 100644
index 0000000000..715fe27a5c
--- /dev/null
+++ b/activejob/lib/active_job/serializers/duration_serializer.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Serializers
+    class DurationSerializer < ObjectSerializer # :nodoc:
+      def serialize(duration)
+        super("value" => duration.value, "parts" => Arguments.serialize(duration.parts))
+      end
+
+      def deserialize(hash)
+        value = hash["value"]
+        parts = Arguments.deserialize(hash["parts"])
+
+        klass.new(value, parts)
+      end
+
+      private
+
+        def klass
+          ActiveSupport::Duration
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/serializers/object_serializer.rb b/activejob/lib/active_job/serializers/object_serializer.rb
new file mode 100644
index 0000000000..1dfd1e44be
--- /dev/null
+++ b/activejob/lib/active_job/serializers/object_serializer.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Serializers
+    # Base class for serializing and deserializing custom objects.
+    #
+    # Example:
+    #
+    #   class MoneySerializer < ActiveJob::Serializers::ObjectSerializer
+    #     def serialize(money)
+    #       super("amount" => money.amount, "currency" => money.currency)
+    #     end
+    #
+    #     def deserialize(hash)
+    #       Money.new(hash["amount"], hash["currency"])
+    #     end
+    #
+    #     private
+    #
+    #       def klass
+    #         Money
+    #       end
+    #   end
+    class ObjectSerializer
+      include Singleton
+
+      class << self
+        delegate :serialize?, :serialize, :deserialize, to: :instance
+      end
+
+      # Determines if an argument should be serialized by a serializer.
+      def serialize?(argument)
+        argument.is_a?(klass)
+      end
+
+      # Serializes an argument to a JSON primitive type.
+      def serialize(hash)
+        { Arguments::OBJECT_SERIALIZER_KEY => self.class.name }.merge!(hash)
+      end
+
+      # Deserilizes an argument form a JSON primiteve type.
+      def deserialize(_argument)
+        raise NotImplementedError
+      end
+
+      private
+
+        # The class of the object that will be serialized.
+        def klass # :doc:
+          raise NotImplementedError
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/serializers/symbol_serializer.rb b/activejob/lib/active_job/serializers/symbol_serializer.rb
new file mode 100644
index 0000000000..7e1f9553a2
--- /dev/null
+++ b/activejob/lib/active_job/serializers/symbol_serializer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Serializers
+    class SymbolSerializer < ObjectSerializer # :nodoc:
+      def serialize(argument)
+        super("value" => argument.to_s)
+      end
+
+      def deserialize(argument)
+        argument["value"].to_sym
+      end
+
+      private
+
+        def klass
+          Symbol
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/serializers/time_serializer.rb b/activejob/lib/active_job/serializers/time_serializer.rb
new file mode 100644
index 0000000000..fe20772f35
--- /dev/null
+++ b/activejob/lib/active_job/serializers/time_serializer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Serializers
+    class TimeSerializer < ObjectSerializer # :nodoc:
+      def serialize(time)
+        super("value" => time.iso8601)
+      end
+
+      def deserialize(hash)
+        Time.iso8601(hash["value"])
+      end
+
+      private
+
+        def klass
+          Time
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/serializers/time_with_zone_serializer.rb b/activejob/lib/active_job/serializers/time_with_zone_serializer.rb
new file mode 100644
index 0000000000..43017fc75b
--- /dev/null
+++ b/activejob/lib/active_job/serializers/time_with_zone_serializer.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Serializers
+    class TimeWithZoneSerializer < ObjectSerializer # :nodoc:
+      def serialize(time)
+        super("value" => time.iso8601)
+      end
+
+      def deserialize(hash)
+        Time.iso8601(hash["value"]).in_time_zone
+      end
+
+      private
+
+        def klass
+          ActiveSupport::TimeWithZone
+        end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/timezones.rb b/activejob/lib/active_job/timezones.rb
new file mode 100644
index 0000000000..ac018eb752
--- /dev/null
+++ b/activejob/lib/active_job/timezones.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module ActiveJob
+  module Timezones #:nodoc:
+    extend ActiveSupport::Concern
+
+    included do
+      around_perform do |job, block|
+        Time.use_zone(job.timezone, &block)
+      end
+    end
+  end
+end
diff --git a/activejob/lib/active_job/translation.rb b/activejob/lib/active_job/translation.rb
index fb45c80d67..0fd9b9fc06 100644
--- a/activejob/lib/active_job/translation.rb
+++ b/activejob/lib/active_job/translation.rb
@@ -5,7 +5,7 @@ module ActiveJob
     extend ActiveSupport::Concern
 
     included do
-      around_perform do |job, block, _|
+      around_perform do |job, block|
         I18n.with_locale(job.locale, &block)
       end
     end
diff --git a/activejob/test/cases/argument_serialization_test.rb b/activejob/test/cases/argument_serialization_test.rb
index 7e7f854da0..e5f1f087fe 100644
--- a/activejob/test/cases/argument_serialization_test.rb
+++ b/activejob/test/cases/argument_serialization_test.rb
@@ -13,6 +13,9 @@ class ArgumentSerializationTest < ActiveSupport::TestCase
 
   [ nil, 1, 1.0, 1_000_000_000_000_000_000_000,
     "a", true, false, BigDecimal(5),
+    :a, 1.day, Date.new(2001, 2, 3), Time.new(2002, 10, 31, 2, 2, 2, "+02:00"),
+    DateTime.new(2001, 2, 3, 4, 5, 6, "+03:00"),
+    ActiveSupport::TimeWithZone.new(Time.utc(1999, 12, 31, 23, 59, 59), ActiveSupport::TimeZone["UTC"]),
     [ 1, "a" ],
     { "a" => 1 }
   ].each do |arg|
@@ -21,7 +24,7 @@ class ArgumentSerializationTest < ActiveSupport::TestCase
     end
   end
 
-  [ :a, Object.new, self, Person.find("5").to_gid ].each do |arg|
+  [ Object.new, self, Person.find("5").to_gid ].each do |arg|
     test "does not serialize #{arg.class}" do
       assert_raises ActiveJob::SerializationError do
         ActiveJob::Arguments.serialize [ arg ]
@@ -46,6 +49,49 @@ class ArgumentSerializationTest < ActiveSupport::TestCase
     assert_arguments_roundtrip([a: 1, "b" => 2])
   end
 
+  test "serialize a hash" do
+    symbol_key = { a: 1 }
+    string_key = { "a" => 1 }
+    indifferent_access = { a: 1 }.with_indifferent_access
+
+    assert_equal(
+      { "a" => 1, "_aj_symbol_keys" => ["a"] },
+      ActiveJob::Arguments.serialize([symbol_key]).first
+    )
+    assert_equal(
+      { "a" => 1, "_aj_symbol_keys" => [] },
+      ActiveJob::Arguments.serialize([string_key]).first
+    )
+    assert_equal(
+      { "a" => 1, "_aj_hash_with_indifferent_access" => true },
+      ActiveJob::Arguments.serialize([indifferent_access]).first
+    )
+  end
+
+  test "deserialize a hash" do
+    symbol_key = { "a" => 1, "_aj_symbol_keys" => ["a"] }
+    string_key = { "a" => 1, "_aj_symbol_keys" => [] }
+    another_string_key = { "a" => 1 }
+    indifferent_access = { "a" => 1, "_aj_hash_with_indifferent_access" => true }
+
+    assert_equal(
+      { a: 1 },
+      ActiveJob::Arguments.deserialize([symbol_key]).first
+    )
+    assert_equal(
+      { "a" => 1 },
+      ActiveJob::Arguments.deserialize([string_key]).first
+    )
+    assert_equal(
+      { "a" => 1 },
+      ActiveJob::Arguments.deserialize([another_string_key]).first
+    )
+    assert_equal(
+      { "a" => 1 },
+      ActiveJob::Arguments.deserialize([indifferent_access]).first
+    )
+  end
+
   test "should maintain hash with indifferent access" do
     symbol_key = { a: 1 }
     string_key = { "a" => 1 }
@@ -56,6 +102,14 @@ class ArgumentSerializationTest < ActiveSupport::TestCase
     assert_instance_of ActiveSupport::HashWithIndifferentAccess, perform_round_trip([indifferent_access]).first
   end
 
+  test "should maintain time with zone" do
+    Time.use_zone "Alaska" do
+      time_with_zone = Time.new(2002, 10, 31, 2, 2, 2).in_time_zone
+      assert_instance_of ActiveSupport::TimeWithZone, perform_round_trip([time_with_zone]).first
+      assert_arguments_unchanged time_with_zone
+    end
+  end
+
   test "should disallow non-string/symbol hash keys" do
     assert_raises ActiveJob::SerializationError do
       ActiveJob::Arguments.serialize [ { 1 => 2 } ]
diff --git a/activejob/test/cases/exceptions_test.rb b/activejob/test/cases/exceptions_test.rb
index 22fed0a808..bc33d79f61 100644
--- a/activejob/test/cases/exceptions_test.rb
+++ b/activejob/test/cases/exceptions_test.rb
@@ -58,6 +58,13 @@ class ExceptionsTest < ActiveJob::TestCase
     end
   end
 
+  test "custom handling of discarded job" do
+    perform_enqueued_jobs do
+      RetryJob.perform_later "CustomDiscardableError", 2
+      assert_equal "Dealt with a job that was discarded in a custom way", JobBuffer.last_value
+    end
+  end
+
   test "custom handling of job that exceeds retry attempts" do
     perform_enqueued_jobs do
       RetryJob.perform_later "CustomCatchError", 6
diff --git a/activejob/test/cases/job_serialization_test.rb b/activejob/test/cases/job_serialization_test.rb
index 440051c427..5c9994508e 100644
--- a/activejob/test/cases/job_serialization_test.rb
+++ b/activejob/test/cases/job_serialization_test.rb
@@ -54,4 +54,11 @@ class JobSerializationTest < ActiveSupport::TestCase
     job.provider_job_id = "some value set by adapter"
     assert_equal job.provider_job_id, job.serialize["provider_job_id"]
   end
+
+  test "serialize stores the current timezone" do
+    Time.use_zone "Hawaii" do
+      job = HelloJob.new
+      assert_equal "Hawaii", job.serialize["timezone"]
+    end
+  end
 end
diff --git a/activejob/test/cases/serializers_test.rb b/activejob/test/cases/serializers_test.rb
new file mode 100644
index 0000000000..bee0c061bd
--- /dev/null
+++ b/activejob/test/cases/serializers_test.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require "helper"
+require "active_job/serializers"
+
+class SerializersTest < ActiveSupport::TestCase
+  class DummyValueObject
+    attr_accessor :value
+
+    def initialize(value)
+      @value = value
+    end
+
+    def ==(other)
+      self.value == other.value
+    end
+  end
+
+  class DummySerializer < ActiveJob::Serializers::ObjectSerializer
+    def serialize(object)
+      super({ "value" => object.value })
+    end
+
+    def deserialize(hash)
+      DummyValueObject.new(hash["value"])
+    end
+
+    private
+
+      def klass
+        DummyValueObject
+      end
+  end
+
+  setup do
+    @value_object = DummyValueObject.new 123
+    @original_serializers = ActiveJob::Serializers.serializers
+  end
+
+  teardown do
+    ActiveJob::Serializers._additional_serializers = @original_serializers
+  end
+
+  test "can't serialize unknown object" do
+    assert_raises ActiveJob::SerializationError do
+      ActiveJob::Serializers.serialize @value_object
+    end
+  end
+
+  test "will serialize objects with serializers registered" do
+    ActiveJob::Serializers.add_serializers DummySerializer
+
+    assert_equal(
+      { "_aj_serialized" => "SerializersTest::DummySerializer", "value" => 123 },
+      ActiveJob::Serializers.serialize(@value_object)
+    )
+  end
+
+  test "won't deserialize unknown hash" do
+    hash = { "_dummy_serializer" => 123, "_aj_symbol_keys" => [] }
+    error = assert_raises(ArgumentError) do
+      ActiveJob::Serializers.deserialize(hash)
+    end
+    assert_equal(
+      'Serializer name is not present in the argument: {"_dummy_serializer"=>123, "_aj_symbol_keys"=>[]}',
+      error.message
+    )
+  end
+
+  test "won't deserialize unknown serializer" do
+    hash = { "_aj_serialized" => "DoNotExist", "value" => 123 }
+    error = assert_raises(ArgumentError) do
+      ActiveJob::Serializers.deserialize(hash)
+    end
+    assert_equal(
+      "Serializer DoNotExist is not known",
+      error.message
+    )
+  end
+
+  test "will deserialize know serialized objects" do
+    ActiveJob::Serializers.add_serializers DummySerializer
+    hash = { "_aj_serialized" => "SerializersTest::DummySerializer", "value" => 123 }
+    assert_equal DummyValueObject.new(123), ActiveJob::Serializers.deserialize(hash)
+  end
+
+  test "adds new serializer" do
+    ActiveJob::Serializers.add_serializers DummySerializer
+    assert ActiveJob::Serializers.serializers.include?(DummySerializer)
+  end
+
+  test "can't add serializer with the same key twice" do
+    ActiveJob::Serializers.add_serializers DummySerializer
+    assert_no_difference(-> { ActiveJob::Serializers.serializers.size }) do
+      ActiveJob::Serializers.add_serializers DummySerializer
+    end
+  end
+end
diff --git a/activejob/test/cases/timezones_test.rb b/activejob/test/cases/timezones_test.rb
new file mode 100644
index 0000000000..e2095b020d
--- /dev/null
+++ b/activejob/test/cases/timezones_test.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require "helper"
+require "jobs/timezone_dependent_job"
+
+class TimezonesTest < ActiveSupport::TestCase
+  setup do
+    JobBuffer.clear
+  end
+
+  test "it performs the job in the given timezone" do
+    job = TimezoneDependentJob.new("2018-01-01T00:00:00Z")
+    job.timezone = "London"
+    job.perform_now
+
+    assert_equal "Happy New Year!", JobBuffer.last_value
+
+    job = TimezoneDependentJob.new("2018-01-01T00:00:00Z")
+    job.timezone = "Eastern Time (US & Canada)"
+    job.perform_now
+
+    assert_equal "Just 5 hours to go", JobBuffer.last_value
+  end
+end
diff --git a/activejob/test/integration/queuing_test.rb b/activejob/test/integration/queuing_test.rb
index 32ef485c45..7a95d3d039 100644
--- a/activejob/test/integration/queuing_test.rb
+++ b/activejob/test/integration/queuing_test.rb
@@ -110,6 +110,22 @@ class QueuingTest < ActiveSupport::TestCase
     end
   end
 
+  test "current timezone is kept while running perform_later" do
+    skip if adapter_is?(:inline)
+
+    begin
+      current_zone = Time.zone
+      Time.zone = "Hawaii"
+
+      TestJob.perform_later @id
+      wait_for_jobs_to_finish_for(5.seconds)
+      assert job_executed
+      assert_equal "Hawaii", job_executed_in_timezone
+    ensure
+      Time.zone = current_zone
+    end
+  end
+
   test "should run job with higher priority first" do
     skip unless adapter_is?(:delayed_job, :que)
 
diff --git a/activejob/test/jobs/retry_job.rb b/activejob/test/jobs/retry_job.rb
index 9aa99d9a21..82b80fe12b 100644
--- a/activejob/test/jobs/retry_job.rb
+++ b/activejob/test/jobs/retry_job.rb
@@ -10,6 +10,7 @@ class ExponentialWaitTenAttemptsError < StandardError; end
 class CustomWaitTenAttemptsError < StandardError; end
 class CustomCatchError < StandardError; end
 class DiscardableError < StandardError; end
+class CustomDiscardableError < StandardError; end
 
 class RetryJob < ActiveJob::Base
   retry_on DefaultsError
@@ -19,6 +20,7 @@ class RetryJob < ActiveJob::Base
   retry_on CustomWaitTenAttemptsError, wait: ->(executions) { executions * 2 }, attempts: 10
   retry_on(CustomCatchError) { |job, exception| JobBuffer.add("Dealt with a job that failed to retry in a custom way after #{job.arguments.second} attempts. Message: #{exception.message}") }
   discard_on DiscardableError
+  discard_on(CustomDiscardableError) { |job, exception| JobBuffer.add("Dealt with a job that was discarded in a custom way") }
 
   def perform(raising, attempts)
     if executions < attempts
diff --git a/activejob/test/jobs/timezone_dependent_job.rb b/activejob/test/jobs/timezone_dependent_job.rb
new file mode 100644
index 0000000000..41f473d533
--- /dev/null
+++ b/activejob/test/jobs/timezone_dependent_job.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require_relative "../support/job_buffer"
+
+class TimezoneDependentJob < ActiveJob::Base
+  def perform(now)
+    now = now.in_time_zone
+    new_year = localtime(2018, 1, 1)
+
+    if now >= new_year
+      JobBuffer.add("Happy New Year!")
+    else
+      JobBuffer.add("Just #{(new_year - now).div(3600)} hours to go")
+    end
+  end
+
+  private
+
+    def localtime(*args)
+      Time.zone ? Time.zone.local(*args) : Time.utc(*args)
+    end
+end
diff --git a/activejob/test/support/integration/dummy_app_template.rb b/activejob/test/support/integration/dummy_app_template.rb
index 7ea78c3350..b56dd3e591 100644
--- a/activejob/test/support/integration/dummy_app_template.rb
+++ b/activejob/test/support/integration/dummy_app_template.rb
@@ -21,6 +21,7 @@ class TestJob < ActiveJob::Base
     File.open(Rails.root.join("tmp/\#{x}.new"), "wb+") do |f|
       f.write Marshal.dump({
         "locale" => I18n.locale.to_s || "en",
+        "timezone" => Time.zone.try(:name) || "UTC",
         "executed_at" => Time.now.to_r
       })
     end
diff --git a/activejob/test/support/integration/test_case_helpers.rb b/activejob/test/support/integration/test_case_helpers.rb
index f02a32a38e..3d9b265b66 100644
--- a/activejob/test/support/integration/test_case_helpers.rb
+++ b/activejob/test/support/integration/test_case_helpers.rb
@@ -62,4 +62,8 @@ module TestCaseHelpers
     def job_executed_in_locale(id = @id)
       job_data(id)["locale"]
     end
+
+    def job_executed_in_timezone(id = @id)
+      job_data(id)["timezone"]
+    end
 end