merge revision(s) 39495: [Backport #7954]

	* string.c (str_byte_substr): don't set coderange if it's not known.
	  [Bug #7954] [ruby-dev:47108]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@39978 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 21 insertions, 2 deletions

diff --git a/string.c b/string.c
index 6ade42074a..65268e806b 100644
--- a/string.c
+++ b/string.c
@@ -4041,10 +4041,29 @@ str_byte_substr(VALUE str, long beg, long len)
     }
     else {
 	str2 = rb_str_new5(str, p, len);
-	rb_enc_cr_str_copy_for_substr(str2, str);
-	OBJ_INFECT(str2, str);
     }
 
+    str_enc_copy(str2, str);
+
+    if (RSTRING_LEN(str2) == 0) {
+	if (!rb_enc_asciicompat(STR_ENC_GET(str)))
+	    ENC_CODERANGE_SET(str2, ENC_CODERANGE_VALID);
+	else
+	    ENC_CODERANGE_SET(str2, ENC_CODERANGE_7BIT);
+    }
+    else {
+	switch (ENC_CODERANGE(str)) {
+	  case ENC_CODERANGE_7BIT:
+	    ENC_CODERANGE_SET(str2, ENC_CODERANGE_7BIT);
+	    break;
+	  default:
+	    ENC_CODERANGE_SET(str2, ENC_CODERANGE_UNKNOWN);
+	    break;
+	}
+    }
+
+    OBJ_INFECT(str2, str);
+
     return str2;
 }