1 files changed, 27 insertions, 0 deletions
diff --git a/railties/lib/rails/backtrace_cleaner.rb b/railties/lib/rails/backtrace_cleaner.rb
new file mode 100644
index 0000000000..8cc8eb1103
--- /dev/null
+++ b/railties/lib/rails/backtrace_cleaner.rb
@@ -0,0 +1,27 @@
+require 'active_support/backtrace_cleaner'
+
+module Rails
+  class BacktraceCleaner < ActiveSupport::BacktraceCleaner
+    APP_DIRS_PATTERN = /^\/?(app|config|lib|test)/
+    RENDER_TEMPLATE_PATTERN = /:in `_render_template_\w*'/
+
+    def initialize
+      super
+      add_filter   { |line| line.sub("#{Rails.root}/", '') }
+      add_filter   { |line| line.sub(RENDER_TEMPLATE_PATTERN, '') }
+      add_filter   { |line| line.sub('./', '/') } # for tests
+
+      add_gem_filters
+      add_silencer { |line| line !~ APP_DIRS_PATTERN }
+    end
+
+    private
+      def add_gem_filters
+        gems_paths = (Gem.path | [Gem.default_dir]).map { |p| Regexp.escape(p) }
+        return if gems_paths.empty?
+
+        gems_regexp = %r{(#{gems_paths.join('|')})/gems/([^/]+)-([\w.]+)/(.*)}
+        add_filter { |line| line.sub(gems_regexp, '\2 (\3) \4') }
+      end
+  end
+end