Bug #6456: [readline] Readline.point when history edited

• Status: Third Party's Issue
• Assignee: kouji (Kouji Takao)
• Target version: -
• ruby -v: ruby 2.0.0dev (2012-05-19 trunk 35705) [x86_64-linux]

[no6v (Nobuhiro IMAI)]

=begin
以下のように、履歴をたどって編集した時に Readline.point の値がおかしくなるようです。

require "readline"

RUBY_DESCRIPTION # => "ruby 2.0.0dev (2012-05-19 trunk 35705) [x86_64-linux]"
Readline::VERSION # => "6.2"

IO.pipe do |r, w|
Readline.input = r
w << "123\n\cP456\n\cP\n"
Readline.readline("", true) # => "123"
Readline.point # => 3
Readline.readline("", true) # => "123456"
Readline.point # => 3
Readline.readline("", true) # => "123456"
Readline.point # => 6
end

>> 123

>> 123456

>> 123456

=end

[mame (Yusuke Endoh)]

• Status changed from Open to Assigned
• Assignee set to kouji (Kouji Takao)

[Glass_saga (Masaki Matsushita)]

• Status changed from Assigned to Third Party's Issue

Readline.pointの実体はGNU readlineの変数rl_pointですが、次のようなコードで検証したところ

#include <stdlib.h>
#include <stdio.h>
#include <readline/readline.h>
#include <readline/history.h>

int
main() {
const char *prompt = "> ";
char *line = NULL;

while (line = readline(prompt)) {
    add_history(line);
    printf("%d: \"%s\"\n", rl_point, line);
    free(line);
}

clear_history();

return EXIT_SUCCESS;

}

% ./a.out

hoge
4: "hoge"
hogefuga # 履歴から"hoge"を復元し"fuga"を追記
4: "hogefuga"
hogefuga # 履歴から"hogefuga"を復元
8: "hogefuga"

以上のような挙動を示したので、GNU readline側の仕様ないしバグではないかと思われます。