Hi,

when sequoia is installed, then building/signing with dpkg-buildpackage
will fail when it was signed before:

$ dpkg-buildpackage -S -d -nc
dpkg-buildpackage: info: source-only, diff-only upload (original source NOT included)
 signfile ansible_2.7.7+dfsg-1+deb10u3.dsc

  Error: File ../ansible_2.7.7+dfsg-1+deb10u3.dsc.asc exists, use "sq --overwrite ..." to overwrite
dpkg-buildpackage: hint: imported own keys might be missing ownership information, try:
dpkg-buildpackage: hint:   sq pki link authorize --cert FINGERPRINT --all --unconstrained
dpkg-buildpackage: error: failed to sign ../ansible_2.7.7+dfsg-1+deb10u3.dsc file: key is not signature-capable

This is different from using gnupg, where it will happily overwrite the
old signature. In this case the hint that dpkg-buildpackage gives is
also wrong, the key has owneship info and is also signature-capable.

I recommend catching also this error condition, and also adding
--overwrite to the sq invocation to match it with gnupg.

Regards,
Lee