merge revision(s) 55372: [Backport #14179]

	* lib/forwardable.rb (_delegator_method): leave the backtrace
	  untouched during accessor.  forwardable.rb does not appear in
	  the backtrace during delegated method because of tail-call
	  optimization.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@62820 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

4 files changed, 17 insertions, 12 deletions

diff --git a/ChangeLog b/ChangeLog
index 0adc80368f..7fb56da4eb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Mon Mar 19 00:04:08 2018  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/forwardable.rb (_delegator_method): leave the backtrace
+	  untouched during accessor.  forwardable.rb does not appear in
+	  the backtrace during delegated method because of tail-call
+	  optimization.
+
 Sun Mar 18 23:59:32 2018  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	dup String#partition return value
diff --git a/lib/forwardable.rb b/lib/forwardable.rb
index e78b9ed1e0..e2b210423f 100644
--- a/lib/forwardable.rb
+++ b/lib/forwardable.rb
@@ -113,12 +113,9 @@ module Forwardable
   # Version of +forwardable.rb+
   FORWARDABLE_VERSION = "1.1.0"
 
-  FILE_REGEXP = %r"#{Regexp.quote(__FILE__)}"
-
   @debug = nil
   class << self
-    # If true, <tt>__FILE__</tt> will remain in the backtrace in the event an
-    # Exception is raised.
+    # ignored
     attr_accessor :debug
   end
 
@@ -203,8 +200,6 @@ module Forwardable
         def #{ali}(*args, &block)
           begin
             #{accessor}
-          ensure
-            $@.delete_if {|s| ::Forwardable::FILE_REGEXP =~ s} if $@ and !::Forwardable::debug
           end.__send__ :#{method}, *args, &block
         end
       end
diff --git a/test/test_forwardable.rb b/test/test_forwardable.rb
index f678ca4fc7..9d159de826 100644
--- a/test/test_forwardable.rb
+++ b/test/test_forwardable.rb
@@ -225,18 +225,21 @@ class TestForwardable < Test::Unit::TestCase
   class Foo
     extend Forwardable
 
+    attr_accessor :bar
     def_delegator :bar, :baz
     def_delegator :caller, :itself, :c
-
-    class Exception
-    end
   end
 
   def test_backtrace_adjustment
+    obj = Foo.new
+    def (obj.bar = Object.new).baz
+      foo
+    end
     e = assert_raise(NameError) {
-      Foo.new.baz
+      obj.baz
     }
-    assert_not_match(/\/forwardable\.rb/, e.backtrace[0])
+    assert_not_match(/\/forwardable\.rb/, e.backtrace[0],
+                     proc {RubyVM::InstructionSequence.of(obj.method(:baz)).disassemble})
     assert_equal(caller(0, 1)[0], Foo.new.c[0])
   end
 
diff --git a/version.h b/version.h
index 05ef2524c3..e4fb32dccc 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.3.7"
 #define RUBY_RELEASE_DATE "2018-03-19"
-#define RUBY_PATCHLEVEL 420
+#define RUBY_PATCHLEVEL 421
 
 #define RUBY_RELEASE_YEAR 2018
 #define RUBY_RELEASE_MONTH 3