Remove @hidden in mix tasks

Instead, we can use the presence or abscence of @shortdoc
to specify if the task should be shown or not.

Author: José Valim

lib/mix/lib/mix/task.ex

@@ -25,9 +25,7 @@ defmodule Mix.Task do
   There are a couple attributes available in Mix tasks to
   configure them in Mix:
 
-  * `@shortdoc` - shows a short description that appears
-    on `mix help`
-  * `@hidden` - do not show the task in `mix help`
+  * `@shortdoc` - makes the task public with a short description that appears on `mix help`
   * `@recursive` - run the task recursively in umbrella projects
 
   """
@@ -41,7 +39,7 @@ defmodule Mix.Task do
   @doc false
   defmacro __using__(_opts) do
     quote do
-      Enum.each [:shortdoc, :hidden, :recursive],
+      Enum.each [:shortdoc, :recursive],
         &Module.register_attribute(__MODULE__, &1, persist: true)
 
       @behaviour Mix.Task
@@ -109,16 +107,6 @@ defmodule Mix.Task do
     end
   end
 
-  @doc """
-  Checks if the task is hidden or not. Returns a boolean.
-  """
-  def hidden?(module) when is_atom(module) do
-    case List.keyfind module.__info__(:attributes), :hidden, 0 do
-      { :hidden, [bool] } -> bool
-      _ -> false
-    end
-  end
-
   @doc """
   Checks if the task should be run recursively for all sub-apps in
   umbrella projects. Returns `true`, `false` or `:both`.

lib/mix/lib/mix/tasks/app.start.ex

@@ -1,8 +1,6 @@
 defmodule Mix.Tasks.App.Start do
   use Mix.Task
 
-  @hidden true
-  @shortdoc "Start registered apps"
   @recursive true
 
   @moduledoc """

lib/mix/lib/mix/tasks/compile.app.ex

@@ -1,8 +1,6 @@
 defmodule Mix.Tasks.Compile.App do
   use Mix.Task
 
-  @hidden true
-  @shortdoc "Write .app file"
   @recursive true
 
   @moduledoc """

lib/mix/lib/mix/tasks/compile.elixir.ex

@@ -164,13 +164,11 @@ defmodule Mix.Tasks.Compile.Elixir do
   use Mix.Task
   alias Mix.Tasks.Compile.Erlang
 
-  @hidden true
-  @shortdoc "Compile Elixir source files"
   @recursive true
   @manifest ".compile.elixir"
 
   @moduledoc """
-  A task to compile Elixir source files.
+  Compiles Elixir source files.
 
   Elixir is smart enough to recompile only files that changed
   and their dependencies. This means if `lib/a.ex` is invoking

lib/mix/lib/mix/tasks/compile.erlang.ex

@@ -5,13 +5,11 @@ defmodule Mix.Tasks.Compile.Erlang do
 
   use Mix.Task
 
-  @hidden true
-  @shortdoc "Compile Erlang source files"
   @recursive true
   @manifest ".compile.erlang"
 
   @moduledoc """
-  A task to compile Erlang source files.
+  Compile Erlang source files.
 
   When this task runs, it will first check the modification times of
   all files to be compiled and if they haven't been

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

@@ -39,8 +39,8 @@ defmodule Mix.Tasks.Compile do
     docs = lc module inlist modules,
               task = Mix.Task.task_name(module),
               match?("compile." <> _, task),
-              doc = Mix.Task.shortdoc(module) do
-      { task, doc }
+              doc = Mix.Task.moduledoc(module) do
+      { task, first_line(doc) }
     end
 
     max = Enum.reduce docs, 0, fn({ task, _ }, acc) ->
@@ -93,4 +93,8 @@ defmodule Mix.Tasks.Compile do
   defp format(expression, args) do
     :io_lib.format(expression, args) |> iolist_to_binary
   end
+
+  defp first_line(doc) do
+    String.split(doc, "\n", global: false) |> hd |> String.strip |> String.rstrip(?.)
+  end
 end

lib/mix/lib/mix/tasks/compile.leex.ex

@@ -3,13 +3,11 @@ defmodule Mix.Tasks.Compile.Leex do
 
   use Mix.Task
 
-  @hidden true
-  @shortdoc "Compile Leex source files"
   @recursive true
   @manifest ".compile.leex"
 
   @moduledoc """
-  A task to compile Leex source files.
+  Compile Leex source files.
 
   When this task runs, it will check the modification time of every file, and
   if it has changed, the file will be compiled. Files will be

lib/mix/lib/mix/tasks/compile.yecc.ex

@@ -3,13 +3,11 @@ defmodule Mix.Tasks.Compile.Yecc do
 
   use Mix.Task
 
-  @hidden true
-  @shortdoc "Compile Yecc source files"
   @recursive true
   @manifest ".compile.yecc"
 
   @moduledoc """
-  A task to compile Yecc source files.
+  Compile Yecc source files.
 
   When this task runs, it will check the modification time of every file, and
   if it has changed, the file will be compiled. Files will be

lib/mix/lib/mix/tasks/deps.check.ex

@@ -3,9 +3,6 @@ defmodule Mix.Tasks.Deps.Check do
 
   import Mix.Deps, only: [loaded: 0, format_dep: 1, format_status: 1, check_lock: 2, ok?: 1]
 
-  @hidden true
-  @shortdoc "Check if all dependencies are valid"
-
   @moduledoc """
   Checks if all dependencies are valid and if not, abort.
   Prints the invalid dependencies' status before aborting.

lib/mix/lib/mix/tasks/deps.loadpaths.ex

@@ -1,9 +1,6 @@
 defmodule Mix.Tasks.Deps.Loadpaths do
   use Mix.Task
 
-  @hidden true
-  @shortdoc "Load all dependencies build paths"
-
   @moduledoc """
   Loads all dependencies for the current build.
   This is invoked directly by `loadpaths` when