Remove unnecessary or incorrect calls to connection_handler

activerecord/lib/active_record/connection_adapters/abstract/connection_handler.rb

@@ -174,8 +174,6 @@ def retrieve_connection(connection_name, role: ActiveRecord::Base.current_role,
         unless pool
           if shard != ActiveRecord::Base.default_shard
             message = "No connection pool for '#{connection_name}' found for the '#{shard}' shard."
-          elsif ActiveRecord::Base.connection_handler != ActiveRecord::Base.default_connection_handler
-            message = "No connection pool for '#{connection_name}' found for the '#{ActiveRecord::Base.current_role}' role."
           elsif role != ActiveRecord::Base.default_role
             message = "No connection pool for '#{connection_name}' found for the '#{role}' role."
           else

activerecord/test/cases/adapters/mysql2/mysql2_adapter_test.rb

@@ -8,7 +8,6 @@ class Mysql2AdapterTest < ActiveRecord::Mysql2TestCase
 
   def setup
     @conn = ActiveRecord::Base.connection
-    @connection_handler = ActiveRecord::Base.connection_handler
   end
 
   def test_connection_error

activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb

@@ -13,7 +13,6 @@ class PostgreSQLAdapterTest < ActiveRecord::PostgreSQLTestCase
 
       def setup
         @connection = ActiveRecord::Base.connection
-        @connection_handler = ActiveRecord::Base.connection_handler
       end
 
       def test_connection_error

activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb

@@ -19,8 +19,6 @@ def setup
         @conn = Base.sqlite3_connection database: ":memory:",
                                         adapter: "sqlite3",
                                         timeout: 100
-
-        @connection_handler = ActiveRecord::Base.connection_handler
       end
 
       def test_bad_connection

activerecord/test/cases/connection_adapters/connection_handlers_sharding_db_test.rb

@@ -10,13 +10,6 @@ class ConnectionHandlersShardingDbTest < ActiveRecord::TestCase
 
       fixtures :people
 
-      def setup
-        @handler = ConnectionHandler.new
-        db_config = ActiveRecord::Base.configurations.configs_for(env_name: "arunit", name: "primary")
-        @rw_pool = @handler.establish_connection(db_config)
-        @ro_pool = @handler.establish_connection(db_config, role: :reading)
-      end
-
       def teardown
         clean_up_connection_handler
       end
@@ -28,7 +21,7 @@ def test_establishing_a_connection_in_connected_to_block_uses_current_role_and_s
             ActiveRecord::Base.establish_connection(db_config)
             assert_nothing_raised { Person.first }
 
-            assert_equal [:default, :shard_one], ActiveRecord::Base.connection_handler.send(:connection_name_to_pool_manager).fetch("ActiveRecord::Base").instance_variable_get(:@role_to_shard_mapping).values.flat_map(&:keys).uniq
+            assert_equal [:default, :shard_one], ActiveRecord::Base.connection_handler.send(:get_pool_manager, "ActiveRecord::Base").shard_names
           end
         end
 
@@ -230,11 +223,8 @@ def test_connects_to_raises_with_a_shard_and_database_key
         end
 
         def test_retrieve_connection_pool_with_invalid_shard
-          assert_not_nil @handler.retrieve_connection_pool("ActiveRecord::Base")
-          assert_nil @handler.retrieve_connection_pool("ActiveRecord::Base", shard: :foo)
-
-          assert_not_nil @handler.retrieve_connection_pool("ActiveRecord::Base", role: :reading)
-          assert_nil @handler.retrieve_connection_pool("ActiveRecord::Base", role: :reading, shard: :foo)
+          assert_not_nil ActiveRecord::Base.connection_handler.retrieve_connection_pool("ActiveRecord::Base")
+          assert_nil ActiveRecord::Base.connection_handler.retrieve_connection_pool("ActiveRecord::Base", shard: :foo)
         end
 
         def test_calling_connected_to_on_a_non_existent_shard_raises

activerecord/test/cases/query_cache_test.rb

@@ -81,12 +81,9 @@ def test_query_cache_is_applied_to_all_connections
     end
 
     mw = middleware { |env|
-      rw_conn = ActiveRecord::Base.connection_handler.connection_pool_list(:writing).first.connection
-      assert_predicate rw_conn, :query_cache_enabled
-
-      ro_conn = ActiveRecord::Base.connection_handler.connection_pool_list(:reading).first.connection
-      assert_predicate ActiveRecord::Base.connection, :query_cache_enabled
-      assert_predicate ro_conn, :query_cache_enabled
+      ActiveRecord::Base.connection_handler.all_connection_pools.each do |pool|
+        assert_predicate pool.connection, :query_cache_enabled
+      end
     }
 
     mw.call({})
@@ -439,14 +436,16 @@ def test_cache_is_available_when_connection_is_connected
 
   def test_cache_is_available_when_using_a_not_connected_connection
     skip "In-Memory DB can't test for using a not connected connection" if in_memory_db?
-    db_config = ActiveRecord::Base.configurations.configs_for(env_name: "arunit", name: "primary").dup
-    new_conn = ActiveRecord::Base.connection_handler.establish_connection(db_config)
+    db_config = ActiveRecord::Base.connection_db_config
+    original_connection = ActiveRecord::Base.remove_connection
+
+    ActiveRecord::Base.establish_connection(db_config)
     assert_not_predicate Task, :connected?
 
     Task.cache do
       assert_queries(1) { Task.find(1); Task.find(1) }
     ensure
-      ActiveRecord::Base.connection_handler.remove_connection_pool(new_conn)
+      ActiveRecord::Base.establish_connection(original_connection)
     end
   end
 
@@ -559,7 +558,7 @@ def test_query_caching_is_local_to_the_current_thread
 
   def test_query_cache_is_enabled_on_all_connection_pools
     middleware {
-      ActiveRecord::Base.connection_handler.connection_pool_list.each do |pool|
+      ActiveRecord::Base.connection_handler.all_connection_pools.each do |pool|
         assert pool.query_cache_enabled
         assert pool.connection.query_cache_enabled
       end
@@ -618,7 +617,7 @@ def test_clear_query_cache_is_called_on_all_connections
 
   private
     def with_temporary_connection_pool(&block)
-      pool_config = ActiveRecord::Base.connection_handler.send(:connection_name_to_pool_manager).fetch("ActiveRecord::Base").get_pool_config(ActiveRecord.writing_role, :default)
+      pool_config = ActiveRecord::Base.connection.pool.pool_config
       new_pool = ActiveRecord::ConnectionAdapters::ConnectionPool.new(pool_config)
 
       pool_config.stub(:pool, new_pool, &block)

activerecord/test/cases/relation/load_async_test.rb

@@ -354,7 +354,6 @@ def setup
         @old_config = ActiveRecord.async_query_executor
         ActiveRecord.async_query_executor = :multi_thread_pool
 
-        handler = ActiveRecord::ConnectionAdapters::ConnectionHandler.new
         config_hash1 = ActiveRecord::Base.configurations.configs_for(env_name: "arunit", name: "primary").configuration_hash
         new_config1 = config_hash1.merge(min_threads: 0, max_threads: 10)
         db_config1 = ActiveRecord::DatabaseConfigurations::HashConfig.new("arunit", "primary", new_config1)
@@ -363,8 +362,11 @@ def setup
         new_config2 = config_hash2.merge(min_threads: 0, max_threads: 10)
         db_config2 = ActiveRecord::DatabaseConfigurations::HashConfig.new("arunit2", "primary", new_config2)
 
-        handler.establish_connection(db_config1)
-        handler.establish_connection(db_config2, owner_name: ARUnit2Model)
+        ActiveRecord::Base.establish_connection(db_config1)
+        ARUnit2Model.establish_connection(db_config2)
+      ensure
+        ActiveRecord::Base.establish_connection(:arunit)
+        ARUnit2Model.establish_connection(:arunit2)
       end
 
       def teardown