[rake] Raise error if cleaning does not succeed.

Fixes https://hipbyte.freshdesk.com/helpdesk/tickets/1359.

NEWS

@@ -18,6 +18,7 @@
     released.
   * Fixed a bug in dispatcher where #super cannot look up the shortcut method.
     (ie #foo=)
+  * Raise error if cleaning a build artefact fails.
   * [iOS] Fixed a bug where `rake device' would no longer print the application
     logs from the device.
   * [OSX] Fixed a bug on OSX platform where compiler flags for iOS are passed

lib/motion/project.rb

@@ -40,14 +40,19 @@ system("/usr/bin/ruby \"#{motion_bin_path}\" update --check")
 
 desc "Clear local build objects"
 task :clean do
-  App.info 'Delete', App.config.build_dir
-  rm_rf(App.config.build_dir)
-  App.config.vendor_projects.each { |vendor| vendor.clean }
-  Dir.glob(App.config.resources_dirs.flatten.map{ |x| x + '/**/*.{nib,storyboardc,momd}' }).each do |p|
+  paths = [App.config.build_dir]
+  paths.concat(Dir.glob(App.config.resources_dirs.flatten.map{ |x| x + '/**/*.{nib,storyboardc,momd}' }))
+  paths.each do |p|
     next if File.extname(p) == ".nib" && !File.exist?(p.sub(/\.nib$/, ".xib"))
     App.info 'Delete', p
     rm_rf p
+    if File.exist?(p)
+      # It can happen that because of file permissions a dir/file is not
+      # actually removed, which can lead to confusing issues.
+      App.fail "Failed to remove `#{p}'. Please remove this path manually."
+    end
   end
+  App.config.vendor_projects.each { |vendor| vendor.clean }
 end
 
 namespace :clean do

lib/motion/project/vendor.rb

@@ -52,6 +52,11 @@ module Motion; module Project;
         if File.exist?(build_dir)
           App.info 'Delete', build_dir
           FileUtils.rm_rf build_dir
+          if File.exist?(build_dir)
+            # It can happen that because of file permissions a dir/file is not
+            # actually removed, which can lead to confusing issues.
+            App.fail "Failed to remove `#{build_dir}'. Please remove this path manually."
+          end
         end
       end
     end