Do not expand structs when comparing AST on ExUnit.Diff

4 files changed, 70 insertions, 59 deletions

diff --git a/lib/elixir/lib/macro.ex b/lib/elixir/lib/macro.ex
index 45ce9d228..0e2069582 100644
--- a/lib/elixir/lib/macro.ex
+++ b/lib/elixir/lib/macro.ex
@@ -1478,18 +1478,43 @@ defmodule Macro do
   def operator?(name, arity) when is_atom(name) and is_integer(arity), do: false
 
   @doc """
-  Returns `true` if the given quoted expression is an AST literal.
+  Returns `true` if the given quoted expression represents a quoted literal.
+
+  Atoms, numbers, and functions are always literals. Binaries, lists, tuples,
+  maps, and structs are only literals if all of their terms are also literals.
+
+  ## Examples
+
+      iex> Macro.quoted_literal?(quote(do: "foo"))
+      true
+      iex> Macro.quoted_literal?(quote(do: {"foo", 1}))
+      true
+      iex> Macro.quoted_literal?(quote(do: %{foo: "bar"}))
+      true
+      iex> Macro.quoted_literal?(quote(do: %URI{path: "/"}))
+      true
+      iex> Macro.quoted_literal?(quote(do: URI.parse("/")))
+      false
+      iex> Macro.quoted_literal?(quote(do: {foo, var}))
+      false
+
   """
   @doc since: "1.7.0"
   @spec quoted_literal?(t) :: boolean
   def quoted_literal?(term)
 
+  def quoted_literal?({:__aliases__, _, args}),
+    do: quoted_literal?(args)
+
+  def quoted_literal?({:%, _, [left, right]}),
+    do: quoted_literal?(left) and quoted_literal?(right)
+
+  def quoted_literal?({:%{}, _, args}), do: quoted_literal?(args)
   def quoted_literal?({left, right}), do: quoted_literal?(left) and quoted_literal?(right)
   def quoted_literal?(list) when is_list(list), do: Enum.all?(list, &quoted_literal?/1)
 
-  def quoted_literal?(term) do
-    is_atom(term) or is_number(term) or is_binary(term) or is_function(term)
-  end
+  def quoted_literal?(term),
+    do: is_atom(term) or is_number(term) or is_binary(term) or is_function(term)
 
   @doc """
   Receives an AST node and expands it until it can no longer
diff --git a/lib/elixir/test/elixir/macro_test.exs b/lib/elixir/test/elixir/macro_test.exs
index a50414fb9..8829bf4ca 100644
--- a/lib/elixir/test/elixir/macro_test.exs
+++ b/lib/elixir/test/elixir/macro_test.exs
@@ -939,6 +939,8 @@ defmodule MacroTest do
   test "quoted_literal?/1" do
     assert Macro.quoted_literal?(quote(do: "foo"))
     assert Macro.quoted_literal?(quote(do: {"foo", 1}))
+    assert Macro.quoted_literal?(quote(do: %{foo: "bar"}))
+    assert Macro.quoted_literal?(quote(do: %URI{path: "/"}))
     refute Macro.quoted_literal?(quote(do: {"foo", var}))
   end
 
diff --git a/lib/ex_unit/lib/ex_unit/diff.ex b/lib/ex_unit/lib/ex_unit/diff.ex
index 03cfdb6bb..dd6077a22 100644
--- a/lib/ex_unit/lib/ex_unit/diff.ex
+++ b/lib/ex_unit/lib/ex_unit/diff.ex
@@ -671,66 +671,51 @@ defmodule ExUnit.Diff do
 
   # Structs
 
-  defp compare_struct({:%, _, [struct1, left_map]}, %struct2{} = right, env) do
-    compare_struct(left_map, Map.from_struct(right), struct1, struct2, env)
-  end
-
   defp compare_struct({:%, _, [struct1, left_map]}, right, env) do
-    compare_struct(left_map, right, struct1, nil, env)
+    compare_quoted_struct(left_map, struct1, right, env)
   end
 
-  defp compare_struct({:%{}, _, [{:__struct__, struct1} | left_items]}, %struct2{} = right, env) do
-    compare_struct({:%{}, [], left_items}, right, struct1, struct2, env)
-  end
-
-  defp compare_struct(%struct1{} = left, %struct2{} = right, env) do
-    compare_struct(left, right, struct1, struct2, env)
-  end
-
-  defp compare_struct(%struct1{} = left, right, env) do
-    compare_struct(left, right, struct1, nil, env)
-  end
-
-  defp compare_struct(left, %struct2{} = right, env) do
-    compare_map(left, right, nil, struct2, env)
+  defp compare_struct({:%{}, meta, [{:__struct__, struct1} | left_items]}, right, env) do
+    compare_quoted_struct({:%{}, meta, left_items}, struct1, right, env)
   end
 
   defp compare_struct(left, right, env) do
-    compare_map(left, right, nil, nil, env)
-  end
-
-  defp compare_struct(%{} = left, right, struct1, struct2, env) do
-    if Inspect.impl_for(left) not in [Inspect.Any, Inspect.Map] do
-      inspect_left = inspect(left)
+    compare_struct(
+      left,
+      Map.from_struct(left),
+      right,
+      maybe_struct(left),
+      maybe_struct(right),
+      env
+    )
+  end
+
+  defp compare_struct(%{} = value, left, right, struct1, struct2, env) do
+    if Inspect.impl_for(value) not in [Inspect.Any, Inspect.Map] do
+      inspect_left = inspect(value)
       inspect_right = inspect(right)
 
       if inspect_left != inspect_right do
         compare_string(inspect_left, inspect_right, ?\", env)
       else
-        compare_map(Map.from_struct(left), right, struct1, struct2, env)
+        compare_map(left, right, struct1, struct2, env)
       end
     else
-      compare_map(Map.from_struct(left), right, struct1, struct2, env)
+      compare_map(left, right, struct1, struct2, env)
     end
   end
 
-  defp compare_struct(left_map, right, struct1, struct2, env) do
-    try do
-      pid = self()
-
-      ExUnit.CaptureIO.capture_io(:stderr, fn ->
-        {items, _} = Code.eval_quoted(left_map)
-        send(pid, {:struct, struct(struct1, items)})
-      end)
-
-      receive do
-        {:struct, left} -> compare_struct(left, right, struct1, struct2, env)
-      end
-    rescue
-      _ -> compare_map(left_map, right, struct1, struct2, env)
+  defp compare_quoted_struct({:%{}, _, kw} = map, struct, right, env) do
+    if Macro.quoted_literal?(kw) do
+      compare_struct(struct(struct, kw), map, right, struct, maybe_struct(right), env)
+    else
+      compare_map(map, right, struct, maybe_struct(right), env)
     end
   end
 
+  defp maybe_struct(%name{}), do: name
+  defp maybe_struct(_), do: nil
+
   defp build_struct_result(nil, nil) do
     %__MODULE__{equivalent?: true}
   end
diff --git a/lib/ex_unit/test/ex_unit/diff_test.exs b/lib/ex_unit/test/ex_unit/diff_test.exs
index 17cede47a..2b35771b9 100644
--- a/lib/ex_unit/test/ex_unit/diff_test.exs
+++ b/lib/ex_unit/test/ex_unit/diff_test.exs
@@ -7,7 +7,7 @@ defmodule ExUnit.DiffTest do
   alias ExUnit.{Assertions, Diff}
 
   defmodule User do
-    defstruct [:age]
+    defstruct [:name, :age]
   end
 
   defmodule Person do
@@ -451,7 +451,7 @@ defmodule ExUnit.DiffTest do
     refute_diff(
       %User{age: 16} = %User{age: 21},
       "%ExUnit.DiffTest.User{age: 1-6-}",
-      "%ExUnit.DiffTest.User{age: +2+1}"
+      "%ExUnit.DiffTest.User{age: +2+1, name: nil}"
     )
 
     refute_diff(
@@ -475,18 +475,17 @@ defmodule ExUnit.DiffTest do
     refute_diff(
       %{age: 16, __struct__: Person} = %User{age: 16},
       "%-ExUnit.DiffTest.Person-{age: 16}",
-      "%+ExUnit.DiffTest.User+{age: 16}"
+      "%+ExUnit.DiffTest.User+{age: 16, name: nil}"
     )
 
-    pins = [tweety_one: 21]
-
-    assert_diff(%User{age: ^tweety_one} = %User{age: 21}, [], pins)
+    pins = [twenty_one: 21]
+    assert_diff(%User{age: ^twenty_one} = %User{age: 21}, [], pins)
     assert_diff(%User{age: age} = %User{age: 21}, [age: 21], pins)
 
     refute_diff(
-      %User{^tweety_one => 21} = %User{age: 21},
-      "%ExUnit.DiffTest.User{-^tweety_one => 21-}",
-      "%ExUnit.DiffTest.User{age: 21}",
+      %User{^twenty_one => 21} = %User{age: 21},
+      "%ExUnit.DiffTest.User{-^twenty_one => 21-}",
+      "%ExUnit.DiffTest.User{age: 21, name: nil}",
       pins
     )
 
@@ -495,23 +494,23 @@ defmodule ExUnit.DiffTest do
 
   test "structs outside of match context" do
     assert_diff(%User{age: 16} == %User{age: 16}, [])
-    assert_diff(%{age: 16, __struct__: User} == %User{age: 16}, [])
+    assert_diff(%{age: 16, __struct__: User, name: nil} == %User{age: 16}, [])
 
     refute_diff(
       %User{age: 16} == %{age: 16},
-      "%-ExUnit.DiffTest.User-{age: 16}",
+      "%-ExUnit.DiffTest.User-{age: 16, -name: nil-}",
       "%{age: 16}"
     )
 
     refute_diff(
       %User{age: 16} == %User{age: 21},
-      "%ExUnit.DiffTest.User{age: 1-6-}",
-      "%ExUnit.DiffTest.User{age: +2+1}"
+      "%ExUnit.DiffTest.User{age: 1-6-, name: nil}",
+      "%ExUnit.DiffTest.User{age: +2+1, name: nil}"
     )
 
     refute_diff(
       %User{age: 16} == %Person{age: 21},
-      "%-ExUnit.DiffTest.User-{age: 1-6-}",
+      "%-ExUnit.DiffTest.User-{age: 1-6-, -name: nil-}",
       "%+ExUnit.DiffTest.Person+{age: +2+1}"
     )
   end