From 3d6b48f77c7219eb6431f5cb77f6c5ea29a28ba1 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?Fran=C3=A7ois=20Beausoleil?= <francois@teksol.info>
Date: Wed, 2 Apr 2008 16:04:59 -0400
Subject: [PATCH] New build:checkdeps task to tell the developer which dependencies are missing before attempting build or installation.

This returns a message like the following when a missing dependency is found:
  $ rake install
  (in /home/francois/src/rubinius)
  Checking build dependencies...
  bison --version >/dev/null
  git --version >/dev/null
  ruby --version >/dev/null
  gem --version >/dev/null
  pkg-config --version >/dev/null
  make --version >/dev/null
  libtool --version >/dev/null
  sh: libtool: not found

  You are missing one or more required dependencies (which might have dependencies of their own):
    * libtool

This is very useful for new developers, as missing dependencies can be immediately corrected, instead of having cryptic error messages later in the build process.
---
 Rakefile |   20 +++++++++++++++++++-
 1 files changed, 19 insertions(+), 1 deletions(-)

diff --git a/Rakefile b/Rakefile
index bdf4b4b..085d724 100644
--- a/Rakefile
+++ b/Rakefile
@@ -82,6 +82,7 @@ AllPreCompiled << "runtime/loader.rbc"
 namespace :build do
 
   task :all => %w[
+    build:checkdeps
     build:shotgun
     build:platform
     build:rbc
@@ -125,6 +126,23 @@ namespace :build do
     sh make('vm')
   end
 
+  desc "Checks that you have all required dependencies"
+  task :checkdeps do
+    puts "Checking build dependencies..."
+    missing_dependencies = []
+    %w(bison git ruby gem pkg-config make libtool).each do |dependency|
+      sh dependency + " --version >/dev/null" rescue nil
+      missing_dependencies << dependency if $?.exitstatus == 127
+    end
+
+    unless missing_dependencies.empty? then
+      puts "\nYou are missing one or more required dependencies (which might have dependencies of their own):"
+      puts missing_dependencies.map {|dep| "  * #{dep}"}.join("\n")
+      puts
+      exit 1
+    end
+  end
+
   desc "Compiles shotgun (the C-code VM)"
   task :shotgun => %w[configure shotgun/rubinius.bin shotgun/rubinius.local.bin]
 
@@ -167,7 +185,7 @@ end
 # INSTALL TASKS
 
 desc "Install rubinius as rbx"
-task :install => :config_env do
+task :install => %w[build:checkdeps config_env] do
   sh "cd shotgun; #{make "install"}"
 
   mkdir_p RBAPATH, :verbose => true
-- 
1.5.3.6