Dice up ActiveSupport::Deprecation

4 files changed, 186 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/deprecation/behaviors.rb b/activesupport/lib/active_support/deprecation/behaviors.rb
new file mode 100644
index 0000000000..c531a1aa58
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/behaviors.rb
@@ -0,0 +1,32 @@
+module ActiveSupport
+  module Deprecation
+    class << self
+      # Behavior is a block that takes a message argument.
+      attr_writer :behavior
+
+      # Whether to print a backtrace along with the warning.
+      attr_accessor :debug
+
+      def behavior
+        @behavior ||= default_behavior
+      end
+
+      def default_behavior
+        Deprecation::DEFAULT_BEHAVIORS[defined?(Rails) ? Rails.env.to_s : 'test']
+      end
+    end
+
+    # Default warning behaviors per Rails.env. Ignored in production.
+    DEFAULT_BEHAVIORS = {
+      'test' => Proc.new { |message, callstack|
+         $stderr.puts(message)
+         $stderr.puts callstack.join("\n  ") if debug
+       },
+      'development' => Proc.new { |message, callstack|
+         logger = defined?(Rails) ? Rails.logger : Logger.new($stderr)
+         logger.warn message
+         logger.debug callstack.join("\n  ") if debug
+       }
+    }
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/method_wrappers.rb b/activesupport/lib/active_support/deprecation/method_wrappers.rb
new file mode 100644
index 0000000000..845bef059f
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/method_wrappers.rb
@@ -0,0 +1,27 @@
+require 'active_support/core_ext/module/deprecation'
+
+module ActiveSupport
+  class << Deprecation
+    # Declare that a method has been deprecated.
+    def deprecate_methods(target_module, *method_names)
+      options = method_names.extract_options!
+      method_names += options.keys
+
+      method_names.each do |method_name|
+        target_module.alias_method_chain(method_name, :deprecation) do |target, punctuation|
+          target_module.module_eval(<<-end_eval, __FILE__, __LINE__)
+            def #{target}_with_deprecation#{punctuation}(*args, &block)   # def generate_secret_with_deprecation(*args, &block)
+              ::ActiveSupport::Deprecation.warn(                          #   ::ActiveSupport::Deprecation.warn(
+                ::ActiveSupport::Deprecation.deprecated_method_warning(   #     ::ActiveSupport::Deprecation.deprecated_method_warning(
+                  :#{method_name},                                        #       :generate_secret,
+                  #{options[method_name].inspect}),                       #       "You should use ActiveSupport::SecureRandom.hex(64)"),
+                caller                                                    #     caller
+              )                                                           #   )
+              #{target}_without_deprecation#{punctuation}(*args, &block)  #   generate_secret_without_deprecation(*args, &block)
+            end                                                           # end
+          end_eval
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/lib/active_support/deprecation/proxy_wrappers.rb b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
new file mode 100644
index 0000000000..1c268d0d9c
--- /dev/null
+++ b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
@@ -0,0 +1,72 @@
+module ActiveSupport
+  module Deprecation
+    class DeprecationProxy #:nodoc:
+      instance_methods.each { |m| undef_method m unless m =~ /^__/ }
+
+      # Don't give a deprecation warning on inspect since test/unit and error
+      # logs rely on it for diagnostics.
+      def inspect
+        target.inspect
+      end
+
+      private
+        def method_missing(called, *args, &block)
+          warn caller, called, args
+          target.__send__(called, *args, &block)
+        end
+    end
+
+    class DeprecatedObjectProxy < DeprecationProxy #:nodoc:
+      def initialize(object, message)
+        @object = object
+        @message = message
+      end
+
+      private
+        def target
+          @object
+        end
+
+        def warn(callstack, called, args)
+          ActiveSupport::Deprecation.warn(@message, callstack)
+        end
+    end
+
+    # Stand-in for <tt>@request</tt>, <tt>@attributes</tt>, <tt>@params</tt>, etc.
+    # which emits deprecation warnings on any method call (except +inspect+).
+    class DeprecatedInstanceVariableProxy < DeprecationProxy #:nodoc:
+      def initialize(instance, method, var = "@#{method}")
+        @instance, @method, @var = instance, method, var
+      end
+
+      private
+        def target
+          @instance.__send__(@method)
+        end
+
+        def warn(callstack, called, args)
+          ActiveSupport::Deprecation.warn("#{@var} is deprecated! Call #{@method}.#{called} instead of #{@var}.#{called}. Args: #{args.inspect}", callstack)
+        end
+    end
+
+    class DeprecatedConstantProxy < DeprecationProxy #:nodoc:
+      def initialize(old_const, new_const)
+        @old_const = old_const
+        @new_const = new_const
+      end
+
+      def class
+        target.class
+      end
+
+      private
+        def target
+          @new_const.to_s.constantize
+        end
+
+        def warn(callstack, called, args)
+          ActiveSupport::Deprecation.warn("#{@old_const} is deprecated! Use #{@new_const} instead.", callstack)
+        end
+    end
+  end
+end
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