Why doesn’t “kitty confirm_os_window_close -1” work as expected? It still prompts for confirmation when closing on macOS

My kitty terminal asks for confirmation when closing terminal windows even though I set it to:

confirm_os_window_close -1

My expectation is that there’s no confirmation prompt if there are no active processes running as in:

USER         PID  %CPU %MEM      VSZ    RSS   TT  STAT STARTED      TIME COMMAND
root       54964   0.0  0.0 410732208   2032 s000  R+   10:54AM   0:00.01 ps au
me         54803   0.0  0.1 410998272   4464 s000  S    10:48AM   0:00.03 -bash --posix
root       54801   0.0  0.1 410752848  10064 s000  Ss   10:48AM   0:00.01 /usr/bin/login -f -l -p me /Applications/kitty.app/Contents/MacOS/kitten run-shell --shell /bin/bash --shell-integration enabled --cwd=/Users/me

(macOS terminal.app will ignore the bash and login process and NOT ask for confirmation to close the terminal window.)

Shell and shell integration are set as follows:

$ echo $SHELL
/bin/bash
$ echo $KITTY_SHELL_INTEGRATION
enabled

.config/kitty/kitty.conf has the following entries:

confirm_os_window_close -1
shell .

Alternatives I tried without success

  • confirm_os_window_close 1 : no difference; still being asked to confirm close
  • confirm_os_window_close -1 count-background : same as above
  • confirm_os_window_close 2 : closes without asking to confirm even though process is running (eg. vim opened)
  • confirm_os_window_close -2 : same as above
  • shell /bin/bash : no difference; still being asked to confirm close
  • shell /bin/bash --login --interactive : kitty crashes

Am I missing anything?

EDIT:

confirm_os_window_close 0

is no accepted solution since it will close windows even with processes running. I want no confirmation for idle kitty windows but confirmation for active ones.

EDIT:
The culprit is the bash process. The kitty message:

Are you sure you want to close this tab? It is running: -bash.