Only compute expression to string if necessary

Author: josevalim

lib/ecto/query/builder.ex

@@ -375,8 +375,8 @@ defmodule Ecto.Query.Builder do
 
     params =
       params
-      |> wrap_nil(escaped_left, Macro.to_string(right))
-      |> wrap_nil(escaped_right, Macro.to_string(left))
+      |> wrap_nil(escaped_left, right)
+      |> wrap_nil(escaped_right, left)
 
     {{:{}, [], [comp_op, [], [escaped_left, escaped_right]]}, {params, acc}}
   end
@@ -591,18 +591,20 @@ defmodule Ecto.Query.Builder do
   defp validate_json_field!(unsupported_field),
     do: error!("`#{Macro.to_string(unsupported_field)}` is not a valid json field")
 
-  defp wrap_nil(params, {:{}, _, [:^, _, [ix]]}, compare_str),
-    do: wrap_nil(params, length(params) - ix - 1, compare_str, [])
+  defp wrap_nil(params, {:{}, _, [:^, _, [ix]]}, to_compare),
+    do: wrap_nil(params, length(params) - ix - 1, to_compare, [])
 
-  defp wrap_nil(params, _other, _compare_str), do: params
+  defp wrap_nil(params, _other, _to_compare), do: params
+
+  defp wrap_nil([{val, type} | params], 0, to_compare, acc) do
+    val =
+      quote do: Ecto.Query.Builder.not_nil!(unquote(val), unquote(Macro.to_string(to_compare)))
 
-  defp wrap_nil([{val, type} | params], 0, compare_str, acc) do
-    val = quote do: Ecto.Query.Builder.not_nil!(unquote(val), unquote(compare_str))
     Enum.reverse(acc, [{val, type} | params])
   end
 
-  defp wrap_nil([pair | params], i, compare_str, acc) do
-    wrap_nil(params, i - 1, compare_str, [pair | acc])
+  defp wrap_nil([pair | params], i, to_compare, acc) do
+    wrap_nil(params, i - 1, to_compare, [pair | acc])
   end
 
   defp expand_and_split_fragment(query, env) do
@@ -879,8 +881,9 @@ defmodule Ecto.Query.Builder do
       do: {find_var!(var, vars), field}
 
   def validate_type!({:field, _, [{var, _, context}, field]}, vars, _env)
-    when is_atom(var) and is_atom(context) and (is_atom(field) or is_binary(field)),
-    do: {find_var!(var, vars), field}
+      when is_atom(var) and is_atom(context) and (is_atom(field) or is_binary(field)),
+      do: {find_var!(var, vars), field}
+
   def validate_type!({:field, _, [{var, _, context}, {:^, _, [field]}]}, vars, _env)
       when is_atom(var) and is_atom(context),
       do: {find_var!(var, vars), field}
@@ -1155,10 +1158,9 @@ defmodule Ecto.Query.Builder do
     do:
       error!(
         "expected literal atom or string or interpolated value in #{used_ref}, got: " <>
-        "`#{Macro.to_string(other)}`"
+          "`#{Macro.to_string(other)}`"
       )
 
-
   @doc """
   Called by escaper at runtime to verify that value is an atom.
   """
@@ -1178,7 +1180,7 @@ defmodule Ecto.Query.Builder do
     do: string
 
   def atom_or_string!(other, used_ref),
-    do: error!("expected atom or string in #{used_ref}, got: `#{inspect other}`")
+    do: error!("expected atom or string in #{used_ref}, got: `#{inspect(other)}`")
 
   @doc """
   Checks if the value of a late binding is an interpolation or
@@ -1365,8 +1367,8 @@ defmodule Ecto.Query.Builder do
   end
 
   def quoted_type({:field, _, [{var, _, context}, field]}, vars)
-    when is_atom(var) and is_atom(context) and (is_atom(field) or is_binary(field)),
-    do: {find_var!(var, vars), field}
+      when is_atom(var) and is_atom(context) and (is_atom(field) or is_binary(field)),
+      do: {find_var!(var, vars), field}
 
   def quoted_type({:field, _, [{kind, _, [value]}, field]}, _vars)
       when kind in [:as, :parent_as] and (is_atom(field) or is_binary(field)) do