Deadlock may occur on closing file-handle by `io.popen`.

[hymkor]

1. What version of GopherLua are you using? :

$ git show
commit b0fa786cf4ea360285924c4a7fd42325be57aec8
Merge: 6ea863f 921e332
Author: Yusuke Inuzuka <yuin@inforno.net>
Date:   Mon Apr 16 22:52:41 2018 +0900

2. What version of Go are you using? :
   * go1.10.3
3. What operating system and processor architecture are you using? :
   * windows/amd64
4. What did you do? :

Running the script like dir %windir%\system32 | head -10
( popen_and_break.lua.txt )

local MUCH_OUTPUT_COMMAND="cmd /c dir %windir%\\system32 2>nul"

local pin = io.popen(MUCH_OUTPUT_COMMAND,"r")
if pin then
    local i=0
    for line in pin:lines() do
        i = i + 1
        print(i,line)
        if i > 10 then
            break
        end
    end
    print("try to close")
    pin:close()
    print("done")
end

5. What did you expect to see? :

$ lua5.1.exe popen_and_break.lua
1        ドライブ C のボリューム ラベルは CDrive です
2        ボリューム シリアル番号は 3485-9E2F です
3
4        C:\WINDOWS\system32 のディレクトリ
5
6       2018/06/09  03:19    <DIR>          .
7       2018/06/09  03:19    <DIR>          ..
8       2018/04/13  01:29    <DIR>          0409
9       2018/05/01  07:44    <DIR>          1029
10      2018/05/01  07:44    <DIR>          1033
11      2018/05/01  07:44    <DIR>          1036
try to close
done

6. What did you see instead? :

$ glua.exe popen_and_break.lua
1        (mojibake removed - this is not problem)
2        (mojibake removed - this is not problem)
3
4        C:\WINDOWS\system32(mojibake removed) 
5
6       2018/06/09  03:19    <DIR>          .
7       2018/06/09  03:19    <DIR>          ..
8       2018/04/13  01:29    <DIR>          0409
9       2018/05/01  07:44    <DIR>          1029
10      2018/05/01  07:44    <DIR>          1033
11      2018/05/01  07:44    <DIR>          1036
try to close

done was not displayed and the script would not terminate.
After typing Ctrl-C, I could see the message "done".

[yuin]

@zetamatta I've just fixed the issue in ca850f5 . Could you confirm the issue is fixed?

[hymkor]

@yuin I found it fixed. Thank you for quick response. I would close this issue. 😄