Fix mix iex

Author: José Valim

CHANGELOG.md

@@ -2,6 +2,7 @@
   * [CLI] `--debug-info` is now true by default
   * [ExUnit] Make ExUnit exit happen in two steps allowing developers to add custom `at_exit` hooks
   * [Macro] Improvements to `Macro.to_binary`
+  * [Mix] Mix now prints information as they come when executing git commands and compiling projects
   * [Kernel] Functions defined with `fn` can now handle many clauses
   * [Kernel] Raise an error if clauses with different arities are defined in the same function
   * [Kernel] `function` macro now accepts arguments in `M.f/a` format

Makefile

@@ -15,7 +15,7 @@ define APP_TEMPLATE
 $(1): lib/$(1)/ebin/Elixir-$(2).beam lib/$(1)/ebin/$(1).app
 
 lib/$(1)/ebin/$(1).app:
-	@ cd lib/$(1) && ../../bin/elixir ../../bin/mix compile.app
+	@ cd lib/$(1) && ../../bin/mix compile.app
 
 lib/$(1)/ebin/Elixir-$(2).beam: $(wildcard lib/$(1)/lib/*.ex) $(wildcard lib/$(1)/lib/*/*.ex) $(wildcard lib/$(1)/lib/*/*/*.ex)
 	@ echo "==> $(1) (compile)"

bin/mix

@@ -1,3 +1,17 @@
-#!/usr/bin/env elixir
-Mix.start
-Mix.CLI.run
+#!/bin/sh
+readlink_f () {
+  cd "$(dirname "$1")" > /dev/null
+  local filename="$(basename "$1")"
+  if [ -h "$filename" ]; then
+    readlink_f "$(readlink "$filename")"
+  else
+    echo "`pwd -P`/$filename"
+  fi
+}
+
+SELF=$(readlink_f "$0")
+SCRIPT_PATH=$(dirname "$SELF")
+ERL_OPTS=""
+
+if [ "$1" == "iex" ]; then ERL_OPTS="-user Elixir-IEx-CLI -iex wait true"; fi
+exec "$SCRIPT_PATH"/elixir --erl "$ERL_OPTS" -e "Mix.start; Mix.CLI.run" -- "$@"

lib/elixir/lib/kernel.ex

@@ -1483,6 +1483,7 @@ defmodule Kernel do
   differences:
 
   1) Differently from records, exceptions are documented by default;
+
   2) Exceptions **must** implement `message/1` as API that return a
      binary as result;
 
@@ -1519,12 +1520,14 @@ defmodule Kernel do
     case __CALLER__.in_guard? do
       true ->
         quote do
-          is_tuple(unquote(thing)) and :erlang.element(2, unquote(thing)) == :__exception__
+          is_tuple(unquote(thing)) and tuple_size(unquote(thing)) > 1 and
+            :erlang.element(2, unquote(thing)) == :__exception__
         end
       false ->
         quote do
           result = unquote(thing)
-          is_tuple(result) and :erlang.element(2, result) == :__exception__
+          is_tuple(result)  and tuple_size(result) > 1 and
+            :erlang.element(2, result) == :__exception__
         end
     end
   end
@@ -2727,7 +2730,7 @@ defmodule Kernel do
   """
   @spec raise(binary | atom | tuple) :: no_return
   def raise(msg) when is_binary(msg) do
-    :erlang.error RuntimeError.new(message: msg)
+    :erlang.error RuntimeError[message: msg]
   end
 
   def raise(exception) do
@@ -2744,14 +2747,23 @@ defmodule Kernel do
   Any module defined via `defexception` automatically
   defines `exception(args)` that returns a new instance
   of the record and a `exception(args, current)` that
-  works as no-op.
+  updates the current exception.
+
+  Re-raising an exception will retrieve the previous
+  stacktrace so it keps the properties of the original
+  exception.
 
   ## Examples
 
       raise ArgumentError, message: "Sample"
 
   """
   @spec raise(tuple | atom, list) :: no_return
+  def raise(exception, args) when is_tuple(exception) and tuple_size(exception) > 1 and
+      :erlang.element(2, exception) == :__exception__ do
+    :erlang.raise(:error, exception.exception(args), :erlang.get_stacktrace)
+  end
+
   def raise(exception, args) do
     :erlang.error exception.exception(args)
   end

lib/iex/lib/iex.ex

@@ -56,6 +56,34 @@ defmodule IEx do
     list
   end
 
+  @doc """
+  Releases waiting IEx.
+
+  When IEx is started with "-iex wait true",
+  the console does not start until `IEx.release`
+  is invoked.
+
+  It returns `:ok` if IEx is released, `:error`
+  if the wait flag was not set.
+  """
+  def release do
+    case :application.get_env(:iex, :wait) do
+      { :ok, value } ->
+        cond do
+          is_pid(value) ->
+            value <- { :iex_latch, :release }
+            :ok
+          value == true ->
+            receive after: (200 -> release)
+          value == false ->
+            :error
+        end
+      :undefined ->
+        # IEx wasn't even started yet
+        :error
+    end
+  end
+
   @doc """
   Registers options used on inspect.
   """
@@ -67,10 +95,7 @@ defmodule IEx do
   Returns currently registered inspect options.
   """
   def inspect_opts do
-    case :application.get_env(:iex, :inspect_opts) do
-      { :ok, list } -> list
-      :undefined -> [limit: 50]
-    end
+    :application.get_env(:iex, :inspect_opts)
   end
 
   @doc """
@@ -114,9 +139,7 @@ defmodule IEx do
         if is_atom(remsh), do: remsh, else: binary_to_atom(remsh)
       end
 
-    function = fn ->
-      start config
-    end
+    function = fn -> start(config) end
 
     args =
       if remote do
@@ -150,6 +173,8 @@ defmodule IEx do
       Process.flag(:trap_exit, true)
 
       preload()
+      wait_until_release()
+
       set_expand_fun()
       run_after_spawn()
       IEx.Loop.start(config)
@@ -158,8 +183,20 @@ defmodule IEx do
 
   ## Boot Helpers
 
-  def boot_config(opts) do
-    scope  = :elixir.scope_for_eval(
+  defp wait_until_release do
+    { :ok, wait } = :application.get_env(:iex, :wait)
+
+    if wait do
+      :application.set_env(:iex, :wait, self())
+
+      receive do
+        { :iex_latch, :release } -> :ok
+      end
+    end
+  end
+
+  defp boot_config(opts) do
+    scope = :elixir.scope_for_eval(
       file: "iex",
       delegate_locals_to: IEx.Helpers
     )

lib/iex/mix.exs

@@ -6,6 +6,10 @@ defmodule IEx.Mixfile do
   end
 
   def application do
-    [env: [after_spawn: []]]
+    [env: [
+      after_spawn: [],
+      inspect_opts: [limit: 50],
+      wait: false,
+    ]]
   end
 end

lib/mix/lib/mix/tasks/iex.ex

@@ -11,7 +11,13 @@ defmodule Mix.Tasks.Iex do
   """
   def run(_) do
     Mix.Task.run Mix.project[:prepare_task]
-    IEx.run
-    :timer.sleep(:infinity)
+    case IEx.release do
+      :ok ->
+        :timer.sleep(:infinity)
+      :error ->
+        raise Mix.Error, message: "could not start IEx. Due to booting constraints, " <>
+          "IEx needs to be started on its own, like `mix iex` and it cannot be mixed " <>
+          "with other tasks as in `mix do compile, iex`"
+    end
   end
 end

lib/mix/test/mix/cli_test.exs

@@ -5,7 +5,7 @@ defmodule Mix.CLITest do
 
   test "env" do
     in_fixture "custom_mixfile", fn ->
-      env = System.cmd %b(MIX_ENV=prod #{elixir_executable} #{mix_executable} run "IO.puts Mix.env")
+      env = System.cmd %b(MIX_ENV=prod #{mix_executable} run "IO.puts Mix.env")
       assert env =~ %r"prod"
     end
   end

lib/mix/test/test_helper.exs

@@ -66,7 +66,7 @@ defmodule MixTest.Case do
   end
 
   def mix(args) do
-    System.cmd "#{elixir_executable} #{mix_executable} #{args}"
+    System.cmd "#{mix_executable} #{args}"
   end
 
   def mix_executable do