stringio.c: ASCII-8BIT StringIO rejects no encodings

* ext/stringio/stringio.c (strio_write): ASCII-8BIT StringIO
  should be writable any encoding strings, without conversion.
  [ruby-core:65240] [Bug ruby#10285]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47716 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Conflicts:
	ChangeLog

Author: nobu

ChangeLog

@@ -1,3 +1,9 @@
+Fri Sep 26 12:52:36 2014  Nobuyoshi Nakada  <[email protected]>
+
+	* ext/stringio/stringio.c (strio_write): ASCII-8BIT StringIO
+	  should be writable any encoding strings, without conversion.
+	  [ruby-core:65240] [Bug #10285]
+
 Wed Sep 24 02:30:55 2014  Nobuyoshi Nakada  <[email protected]>
 
 	* parse.y (parse_ident): just after a label, new expression should

ext/stringio/stringio.c

@@ -1169,12 +1169,13 @@ strio_write(VALUE self, VALUE str)
     struct StringIO *ptr = writable(self);
     long len, olen;
     rb_encoding *enc, *enc2;
+    rb_encoding *const ascii8bit = rb_ascii8bit_encoding();
 
     if (!RB_TYPE_P(str, T_STRING))
 	str = rb_obj_as_string(str);
     enc = rb_enc_get(ptr->string);
     enc2 = rb_enc_get(str);
-    if (enc != enc2 && enc != rb_ascii8bit_encoding()) {
+    if (enc != enc2 && enc != ascii8bit) {
 	str = rb_str_conv_enc(str, enc2, enc);
     }
     len = RSTRING_LEN(str);
@@ -1185,7 +1186,7 @@ strio_write(VALUE self, VALUE str)
 	ptr->pos = olen;
     }
     if (ptr->pos == olen) {
-	if (enc2 == rb_ascii8bit_encoding()) {
+	if (enc == ascii8bit || enc2 == ascii8bit) {
 	    rb_enc_str_buf_cat(ptr->string, RSTRING_PTR(str), len, enc);
 	    OBJ_INFECT(ptr->string, str);
 	}

test/stringio/test_stringio.rb

@@ -137,6 +137,18 @@ def test_write_encoding
     assert_equal(Encoding::UTF_8, s.encoding, "honor the original encoding over ASCII-8BIT")
   end
 
+  def test_set_encoding
+    bug10285 = '[ruby-core:65240] [Bug #10285]'
+    f = StringIO.new()
+    f.set_encoding(Encoding::ASCII_8BIT)
+    f.write("quz \x83 mat".b)
+    s = "foo \x97 bar".force_encoding(Encoding::WINDOWS_1252)
+    assert_nothing_raised(Encoding::CompatibilityError, bug10285) {
+      f.write(s)
+    }
+    assert_equal(Encoding::ASCII_8BIT, f.string.encoding, bug10285)
+  end
+
   def test_mode_error
     f = StringIO.new("", "r")
     assert_raise(IOError) { f.write("foo") }