merges r20624 from trunk into ruby_1_9_1.

* encoding.c (rb_enc_set_default_internal): defines internal
  encoding as nil.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@20697 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 9 insertions, 1 deletions

diff --git a/encoding.c b/encoding.c
index d92a925aa0..eb52f83759 100644
--- a/encoding.c
+++ b/encoding.c
@@ -38,6 +38,7 @@ static struct {
 void rb_enc_init(void);
 
 #define ENCODING_COUNT ENCINDEX_BUILTIN_MAX
+#define UNSPECIFIED_ENCODING INT_MAX
 
 #define enc_autoload_p(enc) (!rb_enc_mbmaxlen(enc))
 
@@ -507,7 +508,12 @@ rb_enc_find_index(const char *name)
     if (i < 0) {
 	i = load_encoding(name);
     }
-    else if (enc_autoload_p(enc = rb_enc_from_index(i))) {
+    else if (!(enc = rb_enc_from_index(i))) {
+	if (i != UNSPECIFIED_ENCODING) {
+	    rb_raise(rb_eArgError, "encoding %s is not registered", name);
+	}
+    }
+    else if (enc_autoload_p(enc)) {
 	if (enc_autoload(enc) < 0) {
 	    rb_warn("failed to load encoding (%s); use ASCII-8BIT instead",
 		    name);
@@ -1111,6 +1117,8 @@ rb_enc_set_default_internal(VALUE encoding)
     if (NIL_P(encoding)) {
 	default_internal_index = -1;
 	default_internal = 0;
+	st_insert(enc_table.names, (st_data_t)strdup("internal"),
+		  (st_data_t)UNSPECIFIED_ENCODING);
 	return;
     }