While testing T6330: Kleopatra: Additional Expiry handling, I got the message that a signing key I had selected wasn't suitable for signing. It turned out that this (test) key was a certify-encryption-authentication key, but not a signing key. Kleopatra still offered this key in the signing certificate drop-down of the Sign/Encrypt dialog.
Turns out that the root cause is a 19 years old workaround for a bug in an ancient version of gpgme.
| rLIBKLEO Libkleo | |||
| rLIBKLEO632057ae9c55 Use Key::canSign instead of Key::canReallySign with new gpgme++ | |||
| rGPGMEPP Gpgme plus plus | |||
| rGPGMEPPeb7817ab7617 cpp: Fix Key::canSign() | |||
| rKLEOPATRA Kleopatra | |||
| rKLEOPATRA70c08d88a093 Use Key::canSign instead of Key::canReallySign with new gpgme++ | |||
| rM GPGME | |||
| rMe80bf34bf86f Update NEWS | |||
| rM5bd84cfd3f09 cpp: Fix Key::canSign() | |||
This works.
There is only a little cosmetic flaw in the UI if you try to do sign+encrypt:
Sign has a check marking it activated but as no key is selected the field behind it is empty and the action button at the end only shows "Encrypt" and of course does just that.
Ideally, as previously sign+encrypt was chosen, I would expect that the action button would get functional only if you removed the check mark before "Sign".
But as this case is pretty exotic, anyway, I won't open a ticket for that.