1 files changed, 55 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/deprecation/reporting.rb b/activesupport/lib/active_support/deprecation/reporting.rb
new file mode 100644
index 0000000000..fcb05ad8d9
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/reporting.rb
@@ -0,0 +1,55 @@
+module ActiveSupport
+  module Deprecation
+    class << self
+      attr_accessor :silenced
+
+      def warn(message = nil, callstack = caller)
+        if behavior && !silenced
+          behavior.call(deprecation_message(callstack, message), callstack)
+        end
+      end
+
+      # Silence deprecation warnings within the block.
+      def silence
+        old_silenced, @silenced = @silenced, true
+        yield
+      ensure
+        @silenced = old_silenced
+      end
+
+      def deprecated_method_warning(method_name, message = nil)
+        warning = "#{method_name} is deprecated and will be removed from Rails #{deprecation_horizon}"
+        case message
+          when Symbol then "#{warning} (use #{message} instead)"
+          when String then "#{warning} (#{message})"
+          else warning
+        end
+      end
+
+      private
+        def deprecation_message(callstack, message = nil)
+          message ||= "You are using deprecated behavior which will be removed from the next major or minor release."
+          "DEPRECATION WARNING: #{message}. #{deprecation_caller_message(callstack)}"
+        end
+
+        def deprecation_caller_message(callstack)
+          file, line, method = extract_callstack(callstack)
+          if file
+            if line && method
+              "(called from #{method} at #{file}:#{line})"
+            else
+              "(called from #{file}:#{line})"
+            end
+          end
+        end
+
+        def extract_callstack(callstack)
+          if md = callstack.first.match(/^(.+?):(\d+)(?::in `(.*?)')?/)
+            md.captures
+          else
+            callstack.first
+          end
+        end
+    end
+  end
+end