enum.c: nil if no iteration

* enum.c (enum_inject): return nil if no iteration, instead of
  Qundef.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47928 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 2 insertions, 0 deletions

diff --git a/enum.c b/enum.c
index b139b69dbb..f05c556844 100644
--- a/enum.c
+++ b/enum.c
@@ -663,6 +663,7 @@ enum_inject(int argc, VALUE *argv, VALUE obj)
     }
     memo = NEW_MEMO(init, Qnil, op);
     rb_block_call(obj, id_each, 0, 0, iter, (VALUE)memo);
+    if (memo->u1.value == Qundef) return Qnil;
     return memo->u1.value;
 }
 
diff --git a/test/ruby/test_enum.rb b/test/ruby/test_enum.rb
index 6448796790..8bcf929690 100644
--- a/test/ruby/test_enum.rb
+++ b/test/ruby/test_enum.rb
@@ -151,6 +151,7 @@ class TestEnumerable < Test::Unit::TestCase
     assert_equal(12, @obj.inject(:*))
     assert_equal(24, @obj.inject(2) {|z, x| z * x })
     assert_equal(24, @obj.inject(2, :*) {|z, x| z * x })
+    assert_equal(nil, @empty.inject() {9})
   end
 
   def test_partition