Signing Git Commits: Inappropriate ioctl for device

When I attempted to sign a Git commit, I encountered the following error:

$ git commit -S -m "important change"
error: gpg failed to sign the data:
[GNUPG:] KEY_CONSIDERED AAAABBBBCCCCDDDD00000 2
[GNUPG:] BEGIN_SIGNING H8
[GNUPG:] PINENTRY_LAUNCHED 583247 curses 1.2.1 - xterm localhost:10.0 - 1000/2001 0
gpg: signing failed: Inappropriate ioctl for device
[GNUPG:] FAILURE sign 83918950
gpg: signing failed: Inappropriate ioctl for device

fatal: failed to write commit object

After an investigation, I learned that the problem could be somethign with gpg itself. To gauge whether it is the problem with gpg, we could sign a message with gpg, e.g.,

$ echo "test" | gpg --clearsign
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

test
gpg: signing failed: Inappropriate ioctl for device
gpg: [stdin]: clear-sign failed: Inappropriate ioctl for device

Clearly, we observe the same error message. We can conclude it is the issue with gpg. It turns out that one reason of this is that tty is not set properly. To fix this, we set tty for gpg using

export GPG_TTY=$(tty)

This can be added to shell script's profiles