mingw shell in emacs

Question

i'd like to use bash shell from msys2 in emacs and i made the following changes in emacs init file:

(setq explicit-shell-file-name "C:/tools/msys64/usr/bin/bash.exe")
(setq shell-file-name "bash")
(setq explicit-bash.exe-args '("--login" "-i"))
(setenv "SHELL" shell-file-name)
(setenv "BASH_ENV" "~/.bashrc")
(setq shell-command-switch "-c")
(add-hook 'comint-output-filter-functions 'comint-strip-ctrl-m)

the shell start and seems work but i got the following error:

bash: cannot set terminal process group (-1): Inappropriate ioctl for device
bash: no job control in this shell

What's the problem?

Answer 1

When I run M-x shell in Emacs from the package mingw64/mingw-w64-x86_64-emacs it reports warnings:

bash: cannot set terminal process group (-1): Inappropriate ioctl for device
bash: no job control in this shell
tput: unknown terminal "emacs"

The reason is the Bash option -i, which is set by default:

(setq explicit-bash-args (list "-i"))

If you remove it the error disappears:

(setq explicit-bash-args
      (if (eq system-type 'windows-nt)
          (list "--login") ; On Windows -i is wrong!
        (list "-i")))

On Windows bash with -i attempts to configure terminal, but Emacs's shell-mode is not a terminal so ioctl reasonably fails!

• https://unix.stackexchange.com/questions/324986/bash-cannot-set-terminal-process-group-1-inappropriate-ioctl-for-device
• https://stackoverflow.com/questions/32090974/what-does-the-shcannot-set-terminal-process-group-1-inappropriate-ioctl-for
• https://stackoverflow.com/questions/72670239/inappropriate-ioctl-for-device-and-no-job-control-when-using-a-pty/