Bug #14388: 不正エンコーディング文字列から切り出した正当なエンコーディング文字列が invalid encoding になる

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux]
• Backport: 2.3: DONE, 2.4: DONE, 2.5: DONE

[tommy (Masahiro Tomita)]

data = "\xFFaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
p data.encoding               #=> #<Encoding:UTF-8>
p data                        #=> "\xFFaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
p data.valid_encoding?        #=> false
data2 = data[1..-1]
p data2                       #=> "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
p data2.valid_encoding?       #=> false
data3 = data2 + ""
p data3.valid_encoding?       #=> true

data は invalid ですが、data から切り出した data2 は valid のはずです。
末尾に空文字列を追加すると valid になります。

[tommy (Masahiro Tomita)]

Rubyの内部のコードにはあんまり詳しくないんですけど、これで直ると思うのですがどうでしょうか。

diff --git a/string.c b/string.c
index 82fa603ada..9079387fac 100644
--- a/string.c
+++ b/string.c
@@ -2560,6 +2560,7 @@ str_substr(VALUE str, long beg, long len, int empty)
 	str2 = str_new_shared(rb_obj_class(str2), str2);
 	RSTRING(str2)->as.heap.ptr += ofs;
 	RSTRING(str2)->as.heap.len = len;
+	ENC_CODERANGE_CLEAR(str2);
     }
     else {
 	if (!len && !empty) return Qnil;

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset trunk|r62040.

---

string.c: clear substring code range

• string.c (str_substr): substring of broken code range string may
  be valid or broken. patch by tommy (Masahiro Tomita) at
  [ruby-dev:50430] [Bug #14388].

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN to 2.3: REQUIRED, 2.4: REQUIRED, 2.5: REQUIRED

[naruse (Yui NARUSE)]

• Backport changed from 2.3: REQUIRED, 2.4: REQUIRED, 2.5: REQUIRED to 2.3: REQUIRED, 2.4: REQUIRED, 2.5: DONE

ruby_2_5 r62483 merged revision(s) 62040.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.3: REQUIRED, 2.4: REQUIRED, 2.5: DONE to 2.3: REQUIRED, 2.4: DONE, 2.5: DONE

ruby_2_4 r62875 merged revision(s) 62040.

[usa (Usaku NAKAMURA)]

• Backport changed from 2.3: REQUIRED, 2.4: DONE, 2.5: DONE to 2.3: DONE, 2.4: DONE, 2.5: DONE

ruby_2_3 r62946 merged revision(s) 62040.