* io.c (rb_io_ext_int_to_encs): ignore internal encoding if external

  encoding is ASCII-8BIT. [Bug #8342]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40610 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 36 insertions, 0 deletions

diff --git a/test/ruby/test_io_m17n.rb b/test/ruby/test_io_m17n.rb
index ec2086186c..ac3b8eaa1e 100644
--- a/test/ruby/test_io_m17n.rb
+++ b/test/ruby/test_io_m17n.rb
@@ -105,6 +105,42 @@ EOT
     }
   end
 
+  def test_open_r_ascii8bit
+    with_tmpdir {
+      generate_file('tmp', "")
+      EnvUtil.with_default_external(Encoding::ASCII_8BIT) do
+        EnvUtil.with_default_internal(Encoding::UTF_8) do
+          open("tmp", "r") {|f|
+            assert_equal(Encoding::ASCII_8BIT, f.external_encoding)
+            assert_equal(nil, f.internal_encoding)
+          }
+          open("tmp", "r:ascii-8bit") {|f|
+            assert_equal(Encoding::ASCII_8BIT, f.external_encoding)
+            assert_equal(nil, f.internal_encoding)
+          }
+          open("tmp", "r:ascii-8bit:utf-16") {|f|
+            assert_equal(Encoding::ASCII_8BIT, f.external_encoding)
+            assert_equal(nil, f.internal_encoding)
+          }
+        end
+        EnvUtil.with_default_internal(nil) do
+          open("tmp", "r") {|f|
+            assert_equal(Encoding::ASCII_8BIT, f.external_encoding)
+            assert_equal(nil, f.internal_encoding)
+          }
+          open("tmp", "r:ascii-8bit") {|f|
+            assert_equal(Encoding::ASCII_8BIT, f.external_encoding)
+            assert_equal(nil, f.internal_encoding)
+          }
+          open("tmp", "r:ascii-8bit:utf-16") {|f|
+            assert_equal(Encoding::ASCII_8BIT, f.external_encoding)
+            assert_equal(nil, f.internal_encoding)
+          }
+        end
+      end
+    }
+  end
+
   def test_open_r_enc_in_opt
     with_tmpdir {
       generate_file('tmp', "")