Reset ansi escapes before newlines in Logger

Closes #14855
Closes #14841

Author: josevalim

lib/ex_unit/test/ex_unit/capture_log_test.exs

@@ -70,15 +70,15 @@ defmodule ExUnit.CaptureLogTest do
       end)
 
     assert logged
-    assert logged =~ "[info] one\n"
-    assert logged =~ "[warning] two\n"
-    assert logged =~ "[debug] three\n"
-    assert logged =~ "[error] one\n"
+    assert logged =~ "[info] one"
+    assert logged =~ "[warning] two"
+    assert logged =~ "[debug] three"
+    assert logged =~ "[error] one"
 
     receive do
       {:nested, logged} ->
-        assert logged =~ "[error] one\n"
-        refute logged =~ "[warning] two\n"
+        assert logged =~ "[error] one"
+        refute logged =~ "[warning] two"
     end
   end
 

lib/ex_unit/test/ex_unit_test.exs

@@ -375,9 +375,9 @@ defmodule ExUnitTest do
     end
 
     output = capture_io(&ExUnit.run/0)
-    refute output =~ "[debug] one\n"
-    assert output =~ "[debug] two\n"
-    assert output =~ "[debug] three\n"
+    refute output =~ "[debug] one"
+    assert output =~ "[debug] two"
+    assert output =~ "[debug] three"
   end
 
   test "supports multi errors" do

lib/logger/lib/logger/formatter.ex

@@ -244,7 +244,20 @@ defmodule Logger.Formatter do
     case if(is_function(enabled, 0), do: enabled.(), else: enabled) do
       true ->
         color = md[:ansi_color] || Map.fetch!(colors, level)
-        [IO.ANSI.format_fragment(color, true), data | IO.ANSI.reset()]
+        fragment = IO.ANSI.format_fragment(color, true)
+        data = IO.iodata_to_binary(data)
+        size = byte_size(data)
+
+        cond do
+          :binary.at(data, size - 2) == ?\r and :binary.at(data, size - 1) == ?\n ->
+            [fragment, binary_part(data, 0, size - 2), IO.ANSI.reset() | "\r\n"]
+
+          :binary.at(data, size - 1) == ?\n ->
+            [fragment, binary_part(data, 0, size - 1), IO.ANSI.reset(), ?\n]
+
+          true ->
+            [fragment, data | IO.ANSI.reset()]
+        end
 
       false ->
         data

lib/logger/test/logger/formatter_test.exs

@@ -97,6 +97,26 @@ defmodule Logger.FormatterTest do
              |> format(formatter)
              |> IO.chardata_to_string() =~ ~r"\d\d\d message"
     end
+
+    test "handles colorize with newlines" do
+      {_, formatter} =
+        new(
+          format: "$message",
+          colors: [enabled: true]
+        )
+
+      assert %{level: :warning, msg: {:string, "message"}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33mmessage\e[0m"
+
+      assert %{level: :warning, msg: {:string, "message\n"}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33mmessage\e[0m\n"
+
+      assert %{level: :warning, msg: {:string, "message\r\n"}, meta: %{}}
+             |> format(formatter)
+             |> IO.chardata_to_string() == "\e[33mmessage\e[0m\r\n"
+    end
   end
 
   describe "compile + format" do