nnn + netbsd-curses + musl libc

[jarun]

Environment details (Put x in the checkbox along with the information)

• Operating System: Ubuntu 20.04 x86_64
• Desktop Environment: XFCE4
• Terminal Emulator: xfce4-terminal
• Shell: zsh
• Custom desktop opener (if applicable): nuke
• Program options used: -acdDEnQrux
• Configuration options set: NNN_PLUG
• Issue exists on nnn master

Exact steps to reproduce the issue

I am seeing an issue with preview-tui-ext with netbsd-curses and musl libc compilation.

Compilation commands used:

$ musl-gcc -O3 -DNORL -DNOMOUSE -DNOBATCH -DTOURBIN_QSORT -DNOSSN -DNOUG -DNOX11 -march=corei7 -I../netbsd-curses/libcurses -o nnn src/nnn.c -Wl,-Bsymbolic-functions -L/opt/netbsd-curses -lcurses -lterminfo -static
$ strip nnn

Plugins are from latest master.

I have set it as p:-preview-tui-ext in NNN_PLUG. I use tmux tmux 3.0a with the config:

# remap prefix from 'C-b' to 'C-\'
unbind C-b 
set-option -g prefix C-c 
bind-key C-c send-prefix

# split panes using | and -
bind | split-window -h
bind - split-window -v
unbind '"' 
unbind %

set -g escape-time 0
set-option -g status off

set -g default-terminal "xterm-256color"

I can repro this with:

• run the plugin with Alt-P
• move up a directory
• close the plugin with Alt-P
• window is broken with the following message: dir changed, range sel off

[jarun]

@luukvbaal can you please take a look?

[luukvbaal]

I tried to reproduce but I don't see the issue. Not sure when I can take another look.

[jarun]

Adding @leovilok.

@luukvbaal Does the message dir changed, range sel off give some ideas? MSG_DIR_CHANGED is used at only one place in nnn.c. It looks like somehow the program has entered the SEL_SELMUL case.

[luukvbaal]

Well the only I can see that happening is if preview-tui-ext somehow passes key presses to nnn right?

[jarun]

Yes, possible. I just tested with preview-tabbed and I don't see this problem.

Also note that I am pressing Alt-P to close the previewer.

[jarun]

OK, I have narrowed it down further to the option -n (nav-to-type mode).

[luukvbaal]

Also note that I am pressing Alt-P to close the previewer.

Yeah I am too, couldn't reproduce yet.

BTW netbsd-curses doesn't seem to play nice with st(suckless' simple terminal). When toggling preview-tui I see flickering of the trailing whitespace in nnn. Doesn't happen when just opening/closing tmux panes though🤔

[jarun]

Yes, there are issues. But it will be good if we can sort those out and support it well.

I am using xfce4-terminal. Another thing I see is (when I restore the terminal by going to parent dir after it breaks), the + sign is shown in statusbar. This definitely tells somehow a wrong keypress is registered.

[jarun]

Does preview-tui(-ext) write something back to nnn when it's closed with the same plugin key?

[jarun]

The assigned key is not the problem BTW, I see it happening with Alt-E and Alt-X as well.

[luukvbaal]

Does preview-tui(-ext) write something back to nnn when it's closed with the same plugin key?

If it does it's not intended. Toggling is done by killing the cat "$NNN_FIFO" pipe.

Could you try

@@ -430,6 +430,6 @@ else
         printf "\$KITTY_LISTEN_ON not set!\nPlease read Usage in preview-tui-ext."
         cfg=$(stty -g); stty raw -echo; head -c 1; stty "$cfg"
     else
-        togglepreview "$1" &
+        togglepreview "$1" > "`~/test &
     fi
 fi

cat ~/test

[jarun]

Checking it... one more thing... irrespective of the key I assign, only for this plugin, as soon as I start the plugin I see * in the statusbar, which means range selection gets enabled. That's why we are seeing the message when we change the directory.

[luukvbaal]

But this behavior is still specific to the netbsd-curses and musl libc compilation right?

[jarun]

With that change the previewer doesn't show.
But I think our issue is not with the plugin. Even if I edit a text file by opening it in vim, I see the range selection getting set.

[jarun]

But this behavior is still specific to the netbsd-curses and musl libc compilation right?

That's correct.

If we can claim good support for this combination, we can auto-generate a static binary with the next release. The numbers are amazing! So I am using it exclusively for a while.

[luukvbaal]

I see, weird stuff. I'm off to bed for now though, good luck.

[jarun]

Yes sure, I can repro this easily with the text file open. So I can continue debugging.

Good night!

[jarun]

Unrelated to this issue.

I see sabotabge-linux has a recipe for nnn but the version is dated.

@rofl0r can you please update it to use the latest nnn v4.0?

Question: is there a nsdbsd-curses specific macro we can use to port the changes upstream?

[jarun]

@luukvbaal I have explained the issue in sabotage-linux/netbsd-curses#46. netbsd-curses sends a NULL (0) which is registered as ^Space (mark range/clear sel keybind) in nnn.

See if the flickering issue on st is also due to the same problem.

I am considering removing the ^Space keybind and just leave the m. As someone who uses the nav-to-type mode exclusively, I find it hard remembering the ^Space key all the time. Maybe because it's seldom used.

Attached the debug logs to show the difference between ncursesw and netbsd-curses behaviour.

nnndbg_ncurses.txt
nnndbg_netbsd.txt

[luukvbaal]

No the problem is still there, although it seems to go away after changing directories:

Was also able to confirm that it's a problem only occurring with netbsd-curses in combination with the alpha patch, issue is not present on st master branch. Seems like cells that haven't been written to by netbsd curses are drawn incorrectly by the alpha patch or something.

[jarun]

Thanks for checking it!

While we are at it, and to have the notes for later, I see another issue with xfce4-terminal (no -n) where if I keep opening and closing a text file detached in another tab again and again, the window breaks. The statusbar is printed after the last entry. Not sure if it is due to the same redraw issue we reported.

If I repeat the open and close the file once or twice, the problem goes away.