1 files changed, 22 insertions, 25 deletions

diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
index a628ee4dbd..2ede92feff 100644
--- a/activerecord/lib/active_record/connection_handling.rb
+++ b/activerecord/lib/active_record/connection_handling.rb
@@ -44,21 +44,18 @@ module ActiveRecord
     #
     # The exceptions AdapterNotSpecified, AdapterNotFound and +ArgumentError+
     # may be returned on an error.
-    def establish_connection(spec = nil)
+    def establish_connection(config = nil)
       raise "Anonymous class is not allowed." unless name
 
-      spec     ||= DEFAULT_ENV.call.to_sym
-      resolver =   ConnectionAdapters::ConnectionSpecification::Resolver.new configurations
-      # TODO: uses name on establish_connection, for backwards compatibility
-      spec     =   resolver.spec(spec, self == Base ? "primary" : name)
-      self.connection_specification_name = spec.name
+      config ||= DEFAULT_ENV.call.to_sym
+      spec_name = self == Base ? "primary" : name
+      self.connection_specification_name = spec_name
 
-      unless respond_to?(spec.adapter_method)
-        raise AdapterNotFound, "database configuration specifies nonexistent #{spec.config[:adapter]} adapter"
-      end
+      resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(Base.configurations)
+      spec = resolver.resolve(config).symbolize_keys
+      spec[:name] = spec_name
 
-      remove_connection
-      connection_handler.establish_connection spec
+      connection_handler.establish_connection(spec)
     end
 
     class MergeAndResolveDefaultUrlConfig # :nodoc:
@@ -76,7 +73,7 @@ module ActiveRecord
       private
         def config
           @raw_config.dup.tap do |cfg|
-            if url = ENV['DATABASE_URL']
+            if url = ENV["DATABASE_URL"]
               cfg[@env] ||= {}
               cfg[@env]["url"] ||= url
             end
@@ -95,20 +92,12 @@ module ActiveRecord
 
     # Return the specification name from the current class or its parent.
     def connection_specification_name
-      unless defined?(@connection_specification_name)
-        @connection_specification_name = self == Base ? "primary" : superclass.connection_specification_name
+      if !defined?(@connection_specification_name) || @connection_specification_name.nil?
+        return self == Base ? "primary" : superclass.connection_specification_name
       end
       @connection_specification_name
     end
 
-    def connection_id
-      ActiveRecord::RuntimeRegistry.connection_id ||= Thread.current.object_id
-    end
-
-    def connection_id=(connection_id)
-      ActiveRecord::RuntimeRegistry.connection_id = connection_id
-    end
-
     # Returns the configuration of the associated connection as a hash:
     #
     #  ActiveRecord::Base.connection_config
@@ -120,7 +109,7 @@ module ActiveRecord
     end
 
     def connection_pool
-      connection_handler.retrieve_connection_pool(connection_specification_name) or raise ConnectionNotEstablished
+      connection_handler.retrieve_connection_pool(connection_specification_name) || raise(ConnectionNotEstablished)
     end
 
     def retrieve_connection
@@ -132,7 +121,15 @@ module ActiveRecord
       connection_handler.connected?(connection_specification_name)
     end
 
-    def remove_connection(name = connection_specification_name)
+    def remove_connection(name = nil)
+      name ||= @connection_specification_name if defined?(@connection_specification_name)
+      # if removing a connection that has a pool, we reset the
+      # connection_specification_name so it will use the parent
+      # pool.
+      if connection_handler.retrieve_connection_pool(name)
+        self.connection_specification_name = nil
+      end
+
       connection_handler.remove_connection(name)
     end
 
@@ -141,6 +138,6 @@ module ActiveRecord
     end
 
     delegate :clear_active_connections!, :clear_reloadable_connections!,
-      :clear_all_connections!, :to => :connection_handler
+      :clear_all_connections!, to: :connection_handler
   end
 end