Initial Version of Deprecation for Rails[Koz]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4623 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* First cut of the Rails Deprecation system.   [Koz]
+
 * Strip boolean XML content before checking for 'true' [Rick Olson]
 
 * Customize default BigDecimal formatting. References #5672 [dave@pragprog.com]

activesupport/lib/active_support.rb

@@ -32,6 +32,7 @@
 require 'active_support/clean_logger'
 require 'active_support/dependencies'
 require 'active_support/reloadable'
+require 'active_support/deprecation'
 
 require 'active_support/ordered_options'
 require 'active_support/option_merger'

activesupport/lib/active_support/deprecation.rb

@@ -0,0 +1,46 @@
+module ActiveSupport
+  module Deprecation
+    @@warning_method = :print
+    mattr_accessor :warning_method
+    
+    class << self
+
+      def print_warning(lines)
+        lines.each {|l| $stderr.write("#{l}\n")}
+      end
+      
+      def log_warning(lines)
+        if Object.const_defined?("RAILS_DEFAULT_LOGGER")
+          lines.each {|l| RAILS_DEFAULT_LOGGER.warn l}
+        else
+          print_warning(lines)
+        end
+      end
+      
+      def issue_warning(line)
+        lines = 
+        ["@@@@@@@@@@ Deprecation Warning @@@@@@@@@@", line,
+         "@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"]
+        self.send("#{@@warning_method}_warning", lines)
+      end
+      
+      def instance_method_warning(clazz, method)
+        issue_warning("Your application calls #{clazz}##{method}, which is now deprecated.  Please see the API documents at http://api.rubyonrails.org/ for more information.")
+      end
+    end
+    
+    module ClassMethods
+      def deprecate(method_name)
+        alias_method "#{method_name}_before_deprecation", method_name
+        class_eval(<<-EOS, __FILE__, __LINE__)
+        def #{method_name}(*args)
+          ::ActiveSupport::Deprecation.instance_method_warning(self.class, :#{method_name})
+          #{method_name}_before_deprecation *args
+        end
+        EOS
+      end
+    end
+  end
+end
+
+Object.extend(ActiveSupport::Deprecation::ClassMethods)

activesupport/test/deprecation_test.rb

@@ -0,0 +1,85 @@
+require 'test/unit'
+require File.dirname(__FILE__) + '/../lib/active_support/deprecation'
+
+# Stub out the warnings to allow assertions
+module ActiveSupport
+  module Deprecation
+    class << self
+      def issue_warning(message)
+        @@warning = message
+      end
+      def last_warning
+        @@warning
+      end
+    end
+  end
+end
+
+class DeprecationTestingClass
+
+  def partiallly_deprecated(foo = nil)
+    if foo.nil?
+      ActiveSupport::Deprecation.issue_warning("calling partially_deprecated with foo=nil is now deprecated")
+    end
+  end
+  
+  def not_deprecated
+    2
+  end
+  
+  def deprecated_no_args
+    1
+  end
+  deprecate :deprecated_no_args
+  
+  def deprecated_one_arg(a)
+    a
+  end
+  deprecate :deprecated_one_arg
+  
+  def deprecated_multiple_args(a,b,c)
+    [a,b,c]
+  end
+  deprecate :deprecated_multiple_args
+  
+end
+
+
+class DeprecationTest < Test::Unit::TestCase
+  def setup
+    @dtc = DeprecationTestingClass.new
+    ActiveSupport::Deprecation.issue_warning(nil) # reset
+  end
+  
+  def test_partial_deprecation
+    @dtc.partiallly_deprecated
+    assert_warning_matches /foo=nil/
+  end
+  
+  def test_raises_nothing
+    assert_equal 2, @dtc.not_deprecated
+  end
+  
+  def test_deprecating_class_method
+    assert_equal 1, @dtc.deprecated_no_args
+    assert_deprecation_warning
+    assert_warning_matches /DeprecationTestingClass#deprecated_no_args/
+  end
+  
+  def test_deprecating_class_method_with_argument
+    assert_equal 1, @dtc.deprecated_one_arg(1)
+  end
+  
+  def test_deprecating_class_method_with_argument
+    assert_equal [1,2,3], @dtc.deprecated_multiple_args(1,2,3)
+  end
+  
+  private
+  def assert_warning_matches(rx)
+    assert ActiveSupport::Deprecation.last_warning =~ rx, "The deprecation warning did not match #{rx}"
+  end
+  
+  def assert_deprecation_warning
+    assert_not_nil ActiveSupport::Deprecation.last_warning, "No Deprecation warnings were issued"
+  end
+end