Tell Thor to return the right exit code on failure

middleman-core/lib/middleman-core/cli/build.rb

@@ -53,7 +53,10 @@ module Middleman::Cli
     
     # Static methods
     class << self
-      
+      def exit_on_failure?
+        true
+      end
+
       # Middleman::Base singleton
       #
       # @return [Middleman::Base]

middleman-core/lib/middleman-core/cli/init.rb

@@ -42,6 +42,10 @@ module Middleman::Cli
       thor_group.new([name], options).invoke_all
     end
   end
+
+  def self.exit_on_failure?
+    true
+  end
   
   # Map "i", "new" and "n" to "init"
   Base.map({
@@ -49,4 +53,4 @@ module Middleman::Cli
     "new" => "init",
     "n"   => "init"
   })
-end
+end

middleman-core/lib/middleman-core/cli/server.rb

@@ -51,7 +51,11 @@ module Middleman::Cli
       Middleman::Watcher.start(params)
     end
   end
+
+  def self.exit_on_failure?
+    true
+  end  
   
   # Map "s" to "server"
   Base.map({ "s" => "server" })
-end
+end