Merge branch 'master' into treewip

* master:
  eliminate warnings about multiple primary keys on habtm join tables
  Add methods to array delegation from `Relation`
  Fix button_to's params option to support nested names.
  Dependencies clean up
  Deprecate AC::Parameters#== with a Hash
  Fix AC::Parameters#== with other AC::Parameters
  Tests for AC::Parameters#==
  better docs for ActiveSupport::TestCase#assert_nothing_raised
  remove needless `debug_exception_response_format` config [ci skip]
  partial pass over the API guide [ci skip]
  Fix `unsubscribed` server side behavior
  Use a semaphore to signal message availability
  Fix master build
  Remove github gems from the master bug report templates
  Truncate ActionCable broadcast message to 300 chars
  Remove unused require

4 files changed, 6 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
index b888148841..5fbd79d118 100644
--- a/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
+++ b/activerecord/lib/active_record/associations/builder/has_and_belongs_to_many.rb
@@ -76,6 +76,9 @@ module ActiveRecord::Associations::Builder # :nodoc:
           left_model.retrieve_connection
         end
 
+        def self.primary_key
+          false
+        end
       }
 
       join_model.name                = "HABTM_#{association_name.to_s.camelize}"
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index 91ec921434..5ef434734a 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -1,5 +1,4 @@
 require 'active_record/type'
-require 'active_support/core_ext/benchmark'
 require 'active_record/connection_adapters/determine_if_preparable_visitor'
 require 'active_record/connection_adapters/schema_cache'
 require 'active_record/connection_adapters/sql_type_metadata'
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
index 6aa264d766..6f2e03b370 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb
@@ -118,7 +118,7 @@ module ActiveRecord
         alias :exec_update :exec_delete
 
         def sql_for_insert(sql, pk, id_value, sequence_name, binds) # :nodoc:
-          unless pk
+          if pk.nil?
             # Extract the table from the insert sql. Yuck.
             table_ref = extract_table_ref_from_insert_sql(sql)
             pk = primary_key(table_ref) if table_ref
diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb
index e4e5d63006..2b1ac42395 100644
--- a/activerecord/lib/active_record/relation/delegation.rb
+++ b/activerecord/lib/active_record/relation/delegation.rb
@@ -37,7 +37,8 @@ module ActiveRecord
     # for each different klass, and the delegations are compiled into that subclass only.
 
     delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to_ary, :join,
-      :[], :&, :|, :+, :-, :sample, :shuffle, :reverse, :compact, to: :to_a
+             :[], :&, :|, :+, :-, :sample, :reverse, :compact, :in_groups, :in_groups_of,
+             :shuffle, :split, to: :to_a
 
     delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key,
              :connection, :columns_hash, :to => :klass