Do not define a generic collectable implementation

lib/elixir/lib/collectable.ex

@@ -106,9 +106,3 @@ defimpl Collectable, for: Map do
     end}
   end
 end
-
-defimpl Collectable, for: Tuple do
-  def into({_, fun} = tuple) when is_function(fun, 2) do
-    tuple
-  end
-end

lib/elixir/test/elixir/collectable_test.exs

@@ -4,13 +4,4 @@ defmodule CollectableTest do
   use ExUnit.Case, async: true
 
   doctest Collectable
-
-  test "is implemented for tuples" do
-    fun =  fn
-      list, {:cont, x} -> [x | list]
-      list, :done -> :lists.reverse(list)
-      _, :halt -> :ok
-    end
-    assert Enum.into(1..3, {[], fun}) == [1, 2, 3]
-  end
 end

lib/mix/lib/mix/scm/git.ex

@@ -228,7 +228,7 @@ defmodule Mix.SCM.Git do
     :ok
   end
 
-  defp git!(args, into \\ Mix.shell.into) do
+  defp git!(args, into \\ %Mix.Shell{}) do
     case System.cmd("git", args, into: into, stderr_to_stdout: true) do
       {response, 0} -> response
       {_, _} -> Mix.raise "Command \"git #{Enum.join(args, " ")}\" failed"

lib/mix/lib/mix/shell.ex

@@ -4,35 +4,61 @@ defmodule Mix.Shell do
   """
 
   @doc """
-  Prints the given message to the shell.
+  Prints the given ANSI message to the shell.
   """
-  @callback info(message :: IO.ANSI.ansidata) :: any
+  @callback info(message :: IO.ANSI.ansidata) :: :ok
 
   @doc """
-  Prints the given error to the shell.
+  Prints the given ANSI error to the shell.
   """
-  @callback error(message :: IO.ANSI.ansidata) :: any
+  @callback error(message :: IO.ANSI.ansidata) :: :ok
 
   @doc """
-  Prompts the user for input.
+  Writes data directly into the shell.
   """
-  @callback prompt(message :: String.t) :: String.t
+  @callback write(message :: binary) :: :ok
 
   @doc """
-  Prompts the user for confirmation.
+  Prompts the user for input.
   """
-  @callback yes?(message :: String.t) :: boolean
+  @callback prompt(message :: binary) :: binary
 
   @doc """
-  Returns a collectable to be used when executing commands.
+  Prompts the user for confirmation.
   """
-  @callback into :: Collectable.t
+  @callback yes?(message :: binary) :: boolean
 
   @doc """
   Prints the current application to the shell if
   it was not printed yet.
   """
-  @callback print_app() :: any
+  @callback print_app() :: :ok
+
+  @doc """
+  A collectable shell struct.
+  """
+  defstruct [print_app?: true]
+
+  defimpl Collectable do
+    def into(%Mix.Shell{print_app?: print_app?} = original) do
+      fun = fn
+        {:cont, shell}, {:cont, data} ->
+          shell.write(data)
+          {:cont, shell}
+        {:print, shell}, {:cont, data} ->
+          shell.print_app()
+          shell.write(data)
+          {:cont, shell}
+        _, _ ->
+          original
+      end
+
+      case print_app? do
+        true -> {{:print, Mix.shell}, fun}
+        false -> {{:cont, Mix.shell}, fun}
+      end
+    end
+  end
 
   @doc """
   Returns the printable app name.

lib/mix/lib/mix/shell/io.ex

@@ -15,42 +15,24 @@ defmodule Mix.Shell.IO do
     if name = Mix.Shell.printable_app_name do
       IO.puts "==> #{name}"
     end
+    :ok
   end
 
   @doc """
-  Returns a collectable to be used along side System.cmd.
+  Writes data directly into the shell.
   """
-  def into do
-    fun = fn
-      :ok, {:cont, data} ->
-        print_app()
-        IO.write(data)
-      :ok, _ ->
-        :ok
-    end
-    {:ok, fun}
-  end
-
-  @doc false
-  # TODO: Deprecate on Elixir v1.8
-  def cmd(command, opts \\ []) do
-    print_app? = Keyword.get(opts, :print_app, true)
-    Mix.Shell.cmd(command, opts, fn data ->
-      if print_app?, do: print_app()
-      IO.write(data)
-    end)
-  end
+  defdelegate write(data), to: IO
 
   @doc """
-  Prints the given message to the shell followed by a newline.
+  Prints the given ANSI message to the shell followed by a newline.
   """
   def info(message) do
     print_app()
     IO.puts IO.ANSI.format message
   end
 
   @doc """
-  Prints the given error to the shell followed by a newline.
+  Prints the given ANSI error to the shell followed by a newline.
   """
   def error(message) do
     print_app()
@@ -82,4 +64,14 @@ defmodule Mix.Shell.IO do
   defp red(message) do
     [:red, :bright, message]
   end
+
+  @doc false
+  # TODO: Deprecate on Elixir v1.8
+  def cmd(command, opts \\ []) do
+    print_app? = Keyword.get(opts, :print_app, true)
+    Mix.Shell.cmd(command, opts, fn data ->
+      if print_app?, do: print_app()
+      IO.write(data)
+    end)
+  end
 end

lib/mix/lib/mix/shell/process.ex

@@ -66,28 +66,11 @@ defmodule Mix.Shell.Process do
   end
 
   @doc """
-  Returns a collectable to be used along side System.cmd.
+  Forwards the message to the current process.
   """
-  def into do
-    fun = fn
-      :ok, {:cont, data} ->
-        print_app()
-        send self(), {:mix_shell, :run, [data]}
-        :ok
-      :ok, _ ->
-        :ok
-    end
-    {:ok, fun}
-  end
-
-  @doc false
-  # TODO: Deprecate on Elixir v1.8
-  def cmd(command, opts \\ []) do
-    print_app? = Keyword.get(opts, :print_app, true)
-    Mix.Shell.cmd(command, opts, fn(data) ->
-      if print_app?, do: print_app()
-      send self(), {:mix_shell, :run, [data]}
-    end)
+  def write(data) do
+    send self(), {:mix_shell, :write, [data]}
+    :ok
   end
 
   @doc """
@@ -96,6 +79,7 @@ defmodule Mix.Shell.Process do
   def info(message) do
     print_app()
     send self(), {:mix_shell, :info, [format(message)]}
+    :ok
   end
 
   @doc """
@@ -104,6 +88,7 @@ defmodule Mix.Shell.Process do
   def error(message) do
     print_app()
     send self(), {:mix_shell, :error, [format(message)]}
+    :ok
   end
 
   defp format(message) do
@@ -168,4 +153,14 @@ defmodule Mix.Shell.Process do
       0 -> raise "no shell process input given for yes?/1"
     end
   end
+
+  @doc false
+  # TODO: Deprecate on Elixir v1.8
+  def cmd(command, opts \\ []) do
+    print_app? = Keyword.get(opts, :print_app, true)
+    Mix.Shell.cmd(command, opts, fn(data) ->
+      if print_app?, do: print_app()
+      send self(), {:mix_shell, :run, [data]}
+    end)
+  end
 end

lib/mix/lib/mix/shell/quiet.ex

@@ -15,22 +15,14 @@ defmodule Mix.Shell.Quiet do
   defdelegate print_app, to: Mix.Shell.IO
 
   @doc """
-  Returns a collectable to be used along side System.cmd.
+  Writes nothing to the shell.
   """
-  def into do
-    {:ok, fn :ok, _ -> :ok end}
-  end
-
-  @doc false
-  # TODO: Deprecate on Elixir v1.8
-  def cmd(command, opts \\ []) do
-    Mix.Shell.cmd(command, opts, fn data -> data end)
-  end
+  def write(_data), do: :ok
 
   @doc """
-  Writes nothing to the shell.
+  Prints nothing to the shell.
   """
-  def info(_message), do: nil
+  def info(_message), do: :ok
 
   @doc """
   Prints the error to the shell followed by a newline.
@@ -51,4 +43,10 @@ defmodule Mix.Shell.Quiet do
   "Yes".
   """
   defdelegate yes?(message), to: Mix.Shell.IO
+
+  @doc false
+  # TODO: Deprecate on Elixir v1.8
+  def cmd(command, opts \\ []) do
+    Mix.Shell.cmd(command, opts, fn data -> data end)
+  end
 end

lib/mix/lib/mix/tasks/cmd.ex

@@ -24,7 +24,7 @@ defmodule Mix.Tasks.Cmd do
   def run(args) do
     {args, apps} = parse_apps(args, [])
     if apps == [] or Mix.Project.config[:app] in apps do
-      case Mix.Shell.cmd(Enum.join(args, " "), into: Mix.shell.into) do
+      case Mix.Shell.cmd(Enum.join(args, " "), into: %Mix.Shell{}) do
         0 -> :ok
         status -> exit(status)
       end

lib/mix/lib/mix/tasks/deps.compile.ex

@@ -227,7 +227,7 @@ defmodule Mix.Tasks.Deps.Compile do
   defp do_command(%Mix.Dep{app: app, opts: opts}, config, command, print_app?, env \\ []) do
     File.cd!(opts[:dest], fn ->
       env = [{"ERL_LIBS", Path.join(config[:env_path], "lib")}] ++ env
-      if Mix.shell.cmd(command, print_app: print_app?, env: env) != 0 do
+      if Mix.Shell.cmd(command, env: env, into: %Mix.Shell{print_app?: print_app?}) != 0 do
         Mix.raise "Could not compile dependency #{inspect app}, \"#{command}\" command failed. " <>
           "You can recompile this dependency with \"mix deps.compile #{app}\", update it " <>
           "with \"mix deps.update #{app}\" or clean it with \"mix deps.clean #{app}\""

lib/mix/test/mix/rebar_test.exs

@@ -184,8 +184,8 @@ defmodule Mix.RebarTest do
         assert_received {:mix_shell, :info, ["* Getting git_rebar" <> _]}
 
         Mix.Tasks.Deps.Compile.run []
-        assert_received {:mix_shell, :run, ["===> Compiling git_rebar\n"]}
-        assert_received {:mix_shell, :run, ["===> Compiling rebar_dep\n"]}
+        assert_received {:mix_shell, :write, ["===> Compiling git_rebar\n"]}
+        assert_received {:mix_shell, :write, ["===> Compiling rebar_dep\n"]}
         assert :git_rebar.any_function == :ok
         assert :rebar_dep.any_function == :ok
 
@@ -214,8 +214,8 @@ defmodule Mix.RebarTest do
         assert_received {:mix_shell, :info, ["* Getting git_rebar " <> _]}
 
         Mix.Tasks.Deps.Compile.run []
-        assert_received {:mix_shell, :run, ["===> Compiling git_rebar\n"]}
-        assert_received {:mix_shell, :run, ["===> Compiling rebar_dep\n"]}
+        assert_received {:mix_shell, :write, ["===> Compiling git_rebar\n"]}
+        assert_received {:mix_shell, :write, ["===> Compiling rebar_dep\n"]}
         assert :git_rebar.any_function == :ok
         assert :rebar_dep.any_function == :ok
 

lib/mix/test/mix/shell_test.exs

@@ -8,8 +8,12 @@ defmodule Mix.ShellTest do
   end
 
   test "executes cmd with expressions" do
+    Mix.shell Mix.Shell.IO
+
     assert capture_io(fn ->
-             assert Mix.Shell.cmd("echo first && echo second", into: Mix.Shell.IO.into) == 0
+             assert Mix.Shell.cmd("echo first && echo second", into: %Mix.Shell{}) == 0
            end) |> String.replace(" \n", "\n") == "first\nsecond\n"
+  after
+    Mix.shell Mix.Shell.Process
   end
 end

lib/mix/test/mix/tasks/cmd_test.exs

@@ -9,9 +9,9 @@ defmodule Mix.Tasks.CmdTest do
         Mix.Task.run "cmd", ["echo", "hello"]
         nl = os_newline()
         assert_received {:mix_shell, :info, ["==> bar"]}
-        assert_received {:mix_shell, :run, ["hello" <> ^nl]}
+        assert_received {:mix_shell, :write, ["hello" <> ^nl]}
         assert_received {:mix_shell, :info, ["==> foo"]}
-        assert_received {:mix_shell, :run, ["hello" <> ^nl]}
+        assert_received {:mix_shell, :write, ["hello" <> ^nl]}
       end)
     end
   end
@@ -22,9 +22,9 @@ defmodule Mix.Tasks.CmdTest do
         Mix.Task.run "cmd", ["--app", "bar", "echo", "hello"]
         nl = os_newline()
         assert_received {:mix_shell, :info, ["==> bar"]}
-        assert_received {:mix_shell, :run, ["hello" <> ^nl]}
+        assert_received {:mix_shell, :write, ["hello" <> ^nl]}
         refute_received {:mix_shell, :info, ["==> foo"]}
-        refute_received {:mix_shell, :run, ["hello" <> ^nl]}
+        refute_received {:mix_shell, :write, ["hello" <> ^nl]}
       end)
     end
   end