Handle constant/1 unpacking in Ecto instead of adapters (#4696)

Author: greg-rychlewski

lib/ecto/query/api.ex

@@ -561,7 +561,7 @@ defmodule Ecto.Query.API do
 
   This would be transformed into
 
-      from p in Post, where: fragment(? in (?,?,?), p.id, constant(1), ^2, ^3)
+      from p in Post, where: fragment(? in (?,?,?), p.id, constant(^1), ^2, ^3)
   """
   def splice(list), do: doc!([list])
 

lib/ecto/query/builder.ex

@@ -781,8 +781,7 @@ defmodule Ecto.Query.Builder do
     case expr do
       {:^, _, [expr]} ->
         checked = quote do: Ecto.Query.Builder.constant!(unquote(expr))
-        escaped = {:{}, [], [:constant, [], [checked]]}
-        {escaped, params_acc}
+        {checked, params_acc}
 
       _ ->
         error!(

test/ecto/query_test.exs

@@ -1119,8 +1119,8 @@ defmodule Ecto.QueryTest do
 
       assert {:fragment, _, select_parts} = query.select.expr
       assert {:fragment, _, limit_parts} = query.limit.expr
-      assert [raw: "", expr: {:constant, _, ["hi"]}, raw: ""] = select_parts
-      assert [raw: "", expr: {:constant, _, [1]}, raw: ""] = limit_parts
+      assert [raw: "", expr: "hi", raw: ""] = select_parts
+      assert [raw: "", expr: 1, raw: ""] = limit_parts
 
       msg = "constant(^value) expects `value` to be a string or a number, got `%{}`"
 
@@ -1186,7 +1186,7 @@ defmodule Ecto.QueryTest do
                raw: ",",
                expr: 2,
                raw: ",",
-               expr: {:constant, _, [3]},
+               expr: 3,
                raw: ",",
                expr: {:^, _, [1]},
                raw: ")"