Issue #13957 has been updated by usa (Usaku NAKAMURA).

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

ruby_2_3 r62140 merged revision(s) 60071.

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Bug #13957: readline が SHARABLE_MIDDLE_SUBSTRING=1 を考慮していない
https://bugs.ruby-lang.org/issues/13957#change-70088

* Author: tommy (Masahiro Tomita)
* Status: Closed
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.5.0dev (2017-09-29 trunk 60062) [x86_64-linux]
* Backport: 2.3: DONE, 2.4: DONE
----------------------------------------
SHARABLE_MIDDLE_SUBSTRING=1 でコンパイルしたRubyで、Readline.insert_text の文字列が正しく扱われません。

```
% ruby -rreadline -e 'p Readline.insert_text(("a"*100)[0,24]).line_buffer'
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
```

次のパッチで直ると思います。

```diff
diff --git a/ext/readline/readline.c b/ext/readline/readline.c
index 253798f9e6..deebc282f5 100644
--- a/ext/readline/readline.c
+++ b/ext/readline/readline.c
@@ -93,6 +93,7 @@ static char **readline_attempted_completion_function(const char *text,
 
 #define OutputStringValue(str) do {\
     SafeStringValue(str);\
+    StringValueCStr(str);\
     (str) = rb_str_conv_enc((str), rb_enc_get(str), rb_locale_encoding());\
 } while (0)\
 
```

パッチ適用後

```
% ruby -rreadline -e 'p Readline.insert_text(("a"*100)[0,24]).line_buffer'
"aaaaaaaaaaaaaaaaaaaaaaaa"
```



-- 
https://bugs.ruby-lang.org/