Fix the line number in the backtrace when Module#delegate raises

2 files changed, 14 insertions, 2 deletions

diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb
index 8655288bc3..654e3a01c6 100644
--- a/activesupport/lib/active_support/core_ext/module/delegation.rb
+++ b/activesupport/lib/active_support/core_ext/module/delegation.rb
@@ -133,7 +133,7 @@ class Module
           %(raise "#{self}##{method_prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}")
         end
 
-      module_eval(<<-EOS, file, line - 5)
+      module_eval(<<-EOS, file, line - 1)
         def #{method_prefix}#{method}(*args, &block)        # def customer_name(*args, &block)
           #{to}.#{call}*args, &block)                       #   client.name(*args, &block)
         rescue NoMethodError                                # rescue NoMethodError
diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
index 074a3412d4..c33ade8381 100644
--- a/activesupport/test/core_ext/module_test.rb
+++ b/activesupport/test/core_ext/module_test.rb
@@ -38,9 +38,12 @@ Somewhere = Struct.new(:street, :city) do
   end
 end
 
-Someone   = Struct.new(:name, :place) do
+class Someone < Struct.new(:name, :place)
   delegate :street, :city, :to_f, :protected_method, :private_method, :to => :place
   delegate :upcase, :to => "place.city"
+
+  FAILED_DELEGATE_LINE = __LINE__ + 1
+  delegate :foo, :to => :place
 end
 
 Invoice   = Struct.new(:client) do
@@ -182,6 +185,15 @@ class ModuleTest < Test::Unit::TestCase
     end
   end
 
+  def test_delegation_exception_backtrace
+    someone = Someone.new("foo", "bar")
+    someone.foo
+  rescue NoMethodError => e
+    file_and_line = "#{__FILE__}:#{Someone::FAILED_DELEGATE_LINE}"
+    assert e.backtrace.first.include?(file_and_line),
+           "[#{e.backtrace.first}] did not include [#{file_and_line}]"
+  end
+
   def test_parent
     assert_equal Yz::Zy, Yz::Zy::Cd.parent
     assert_equal Yz, Yz::Zy.parent