Use the shell to run Mix.Shell.cmd commands

Author: ericmj

lib/mix/lib/mix/shell.ex

@@ -38,7 +38,7 @@ defmodule Mix.Shell do
   is shared accross different shells.
   """
   def cmd(command, callback) do
-    port = Port.open({ :spawn, to_char_list(command) },
+    port = Port.open({ :spawn, shell_command(command) },
       [:stream, :binary, :exit_status, :hide, :use_stdio, :stderr_to_stdout])
     do_cmd(port, callback)
   end
@@ -52,4 +52,21 @@ defmodule Mix.Shell do
         status
     end
   end
+
+  # Finding shell command logic from :os.cmd in OTP
+  # https://github.com/erlang/otp/blob/8deb96fb1d017307e22d2ab88968b9ef9f1b71d0/lib/kernel/src/os.erl#L184
+  defp shell_command(command) do
+    command = to_char_list(command)
+
+    case :os.type do
+      { :unix, _ } ->
+        %c(sh -c '#{command}')
+      { :win32, osname } ->
+        case { System.getenv("COMSPEC"), osname } do
+          { false, :windows } -> 'command.com /c #{command}'
+          { false, _ }        -> 'cmd /c #{command}'
+          { false, cmd }      -> '#{cmd} /c #{command}'
+        end
+    end
+  end
 end

lib/mix/test/mix/shell_test.exs

@@ -0,0 +1,44 @@
+Code.require_file "../test_helper.exs", __DIR__
+
+defmodule Mix.ShellTest do
+  use MixTest.Case
+
+  test "shell process" do
+    Mix.shell.info "abc"
+    Mix.shell.error "def"
+    assert_received { :mix_shell, :info, ["abc"] }
+    assert_received { :mix_shell, :error, ["def"] }
+
+    self <- { :mix_shell_input, :yes?, true }
+    assert Mix.shell.yes?("hello?")
+    assert_received { :mix_shell, :yes?, ["hello?"] }
+
+    assert Mix.shell.cmd("echo first") == 0
+    assert_received { :mix_shell, :run, ["first\n"] }
+  end
+
+  test "shell io" do
+    import ExUnit.CaptureIO
+
+    Mix.shell(Mix.Shell.IO)
+    assert Mix.shell == Mix.Shell.IO
+
+    assert capture_io(fn -> Mix.shell.info "abc" end) ==
+           "abc\n"
+
+    assert capture_io(:stderr, fn -> Mix.shell.error "def" end) ==
+           (IO.ANSI.escape "%{red,bright}def") <> "\n"
+
+    capture_io("Yes", fn -> assert Mix.shell.yes?("hello?") end)
+
+    assert capture_io(fn -> assert Mix.shell.cmd("echo first") == 0 end) ==
+           "first\n"
+  after
+    Mix.shell(Mix.Shell.Process)
+  end
+
+  test "shell cmd" do
+    assert Mix.shell.cmd("echo first && echo second") == 0
+    assert_received { :mix_shell, :run, ["first\nsecond\n"] }
+  end
+end