remove custom function workaround

lib/flop/adapter.ex

@@ -52,20 +52,4 @@ defmodule Flop.Adapter do
   @callback list(queryable, opts) :: [any]
 
   @callback get_field(any, atom, Flop.FieldInfo.t()) :: any
-
-  @doc """
-  Returns a quoted function to be compiled in the schema protocol
-  implementation.
-
-  Takes the schema options (with the nested adapter options) as argument.
-
-  This is a hacky workaround that is necessary because
-  `Ecto.Query.API.selected_as/1` does not accept variables, which means that we
-  need to compile a function that builds the `order_by` clause for configured
-  alias fields.
-
-  This callback will be removed as soon as a better solution is found or made
-  possible.
-  """
-  @callback custom_func_builder(opts) :: Macro.t() when opts: keyword
 end

lib/flop/adapter/ecto.ex

@@ -499,66 +499,6 @@ defmodule Flop.Adapter.Ecto do
     Keyword.merge(default_opts, Keyword.get(opts, :query_opts, []))
   end
 
-  ## Compile time shenanigans
-
-  @impl Flop.Adapter
-  def custom_func_builder(opts) do
-    adapter_opts = Keyword.fetch!(opts, :adapter_opts)
-    compound_fields = Map.fetch!(adapter_opts, :compound_fields)
-    join_fields = Map.fetch!(adapter_opts, :join_fields)
-    alias_fields = Map.fetch!(adapter_opts, :alias_fields)
-
-    compound_field_funcs =
-      for {name, fields} <- compound_fields do
-        quote do
-          def custom(struct, {:apply_order_by, q, {direction, unquote(name)}}) do
-            Enum.reduce(unquote(fields), q, fn field, acc_q ->
-              Flop.Schema.custom(
-                struct,
-                {:apply_order_by, acc_q, {direction, field}}
-              )
-            end)
-          end
-        end
-      end
-
-    join_field_funcs =
-      for {join_field, %{binding: binding, field: field}} <- join_fields do
-        quote do
-          def custom(_, {:apply_order_by, q, {direction, unquote(join_field)}}) do
-            order_by(
-              q,
-              [{^unquote(binding), r}],
-              [{^direction, field(r, unquote(field))}]
-            )
-          end
-        end
-      end
-
-    alias_field_func =
-      for name <- alias_fields do
-        quote do
-          def custom(_, {:apply_order_by, q, {direction, unquote(name)}}) do
-            order_by(q, [{^direction, selected_as(unquote(name))}])
-          end
-        end
-      end
-
-    schema_field_func =
-      quote do
-        def custom(_, {:apply_order_by, q, direction}) do
-          order_by(q, ^direction)
-        end
-      end
-
-    [
-      compound_field_funcs,
-      join_field_funcs,
-      alias_field_func,
-      schema_field_func
-    ]
-  end
-
   ## Filter query builder
 
   for op <- [:like_and, :like_or, :ilike_and, :ilike_or] do

lib/flop/schema.ex

@@ -844,10 +844,6 @@ defprotocol Flop.Schema do
   @doc since: "0.2.0"
   @spec max_limit(any) :: pos_integer | nil
   def max_limit(data)
-
-  @doc false
-  @spec custom(any, any) :: any
-  def custom(data, arg)
 end
 
 defimpl Flop.Schema, for: Any do
@@ -926,7 +922,6 @@ defimpl Flop.Schema, for: Any do
 
     field_info_func = build_field_info_func(adapter, adapter_opts, struct)
     get_field_func = build_get_field_func(struct, adapter, adapter_opts)
-    custom_func = adapter.custom_func_builder(options)
 
     quote do
       defimpl Flop.Schema, for: unquote(module) do
@@ -965,8 +960,6 @@ defimpl Flop.Schema, for: Any do
         def sortable(_) do
           unquote(sortable_fields)
         end
-
-        unquote(custom_func)
       end
     end
   end