io.c: preserve encodings

* io.c (rb_io_extract_encoding_option): preserve encodings in
  warning messages.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47305 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 14 insertions, 3 deletions

diff --git a/io.c b/io.c
index ddd9f1a9ff..62a948093d 100644
--- a/io.c
+++ b/io.c
@@ -5194,9 +5194,9 @@ rb_io_extract_encoding_option(VALUE opt, rb_encoding **enc_p, rb_encoding **enc2
     if ((extenc != Qundef || intenc != Qundef) && !NIL_P(encoding)) {
 	if (!NIL_P(ruby_verbose)) {
 	    int idx = rb_to_encoding_index(encoding);
-	    rb_warn("Ignoring encoding parameter '%s': %s_encoding is used",
-		    idx < 0 ? StringValueCStr(encoding) : rb_enc_name(rb_enc_from_index(idx)),
-		    extenc == Qundef ? "internal" : "external");
+	    if (idx >= 0) encoding = rb_enc_from_encoding(rb_enc_from_index(idx));
+	    rb_warn("Ignoring encoding parameter '%"PRIsVALUE"': %s_encoding is used",
+		    encoding, extenc == Qundef ? "internal" : "external");
 	}
 	encoding = Qnil;
     }
diff --git a/test/ruby/test_io_m17n.rb b/test/ruby/test_io_m17n.rb
index e9e6a1cf83..7f54762ebe 100644
--- a/test/ruby/test_io_m17n.rb
+++ b/test/ruby/test_io_m17n.rb
@@ -312,6 +312,17 @@ EOT
     }
   end
 
+  def test_ignored_encoding_option
+    enc = "\u{30a8 30f3 30b3 30fc 30c7 30a3 30f3 30b0}"
+    pattern = /#{enc}/
+    assert_warning(pattern) {
+      open(IO::NULL, external_encoding: "us-ascii", encoding: enc)
+    }
+    assert_warning(pattern) {
+      open(IO::NULL, internal_encoding: "us-ascii", encoding: enc)
+    }
+  end
+
   def test_io_new_enc
     with_tmpdir {
       generate_file("tmp", "\xa1")