Merge pull request #35899 from eileencodes/fix-connection-when-handler-doesnt-exist

Ensure a handler is set when using `connected_to`

1 files changed, 17 insertions, 10 deletions

diff --git a/activerecord/lib/active_record/connection_handling.rb b/activerecord/lib/active_record/connection_handling.rb
index 53069cd899..6782833c5a 100644
--- a/activerecord/lib/active_record/connection_handling.rb
+++ b/activerecord/lib/active_record/connection_handling.rb
@@ -85,14 +85,14 @@ module ActiveRecord
     # based on the requested role:
     #
     #   ActiveRecord::Base.connected_to(role: :writing) do
-    #     Dog.create! # creates dog using dog connection
+    #     Dog.create! # creates dog using dog writing connection
     #   end
     #
     #   ActiveRecord::Base.connected_to(role: :reading) do
     #     Dog.create! # throws exception because we're on a replica
     #   end
     #
-    #   ActiveRecord::Base.connected_to(role: :unknown_ode) do
+    #   ActiveRecord::Base.connected_to(role: :unknown_role) do
     #     # raises exception due to non-existent role
     #   end
     #
@@ -100,11 +100,20 @@ module ActiveRecord
     # you can use +connected_to+ with a +database+ argument. The +database+ argument
     # expects a symbol that corresponds to the database key in your config.
     #
-    # This will connect to a new database for the queries inside the block.
-    #
     #   ActiveRecord::Base.connected_to(database: :animals_slow_replica) do
     #     Dog.run_a_long_query # runs a long query while connected to the +animals_slow_replica+
     #   end
+    #
+    # This will connect to a new database for the queries inside the block. By
+    # default the `:writing` role will be used since all connections must be assigned
+    # a role. If you would like to use a different role you can pass a hash to database:
+    #
+    #   ActiveRecord::Base.connected_to(database: { readonly_slow: :animals_slow_replica }) do
+    #     Dog.run_a_long_query # runs a long query while connected to the +animals_slow_replica+
+    #       using the readonly_slow role.
+    #   end
+    #
+    # When using the database key a new connection will be established every time.
     def connected_to(database: nil, role: nil, &blk)
       if database && role
         raise ArgumentError, "connected_to can only accept a `database` or a `role` argument, but not both arguments."
@@ -112,17 +121,14 @@ module ActiveRecord
         if database.is_a?(Hash)
           role, database = database.first
           role = role.to_sym
-        else
-          role = database.to_sym
         end
 
         config_hash = resolve_config_for_connection(database)
         handler = lookup_connection_handler(role)
 
-        with_handler(role) do
-          handler.establish_connection(config_hash)
-          yield
-        end
+        handler.establish_connection(config_hash)
+
+        with_handler(role, &blk)
       elsif role
         with_handler(role.to_sym, &blk)
       else
@@ -154,6 +160,7 @@ module ActiveRecord
     end
 
     def lookup_connection_handler(handler_key) # :nodoc:
+      handler_key ||= ActiveRecord::Base.writing_role
       connection_handlers[handler_key] ||= ActiveRecord::ConnectionAdapters::ConnectionHandler.new
     end