Signing documentation is wrong and will not work
When talking about provising an in-memory GPG key, the signing documentation states:
The result will be a long, multi-line string that looks like this
-----BEGIN PGP PRIVATE KEY BLOCK-----
lQdGBF4jUfwBEACblZV4uBViHcYLOb2280tEp r64iB9b6YRkWil3EODiiLd9JS3V9pip+B1QLw ... EdLCEJA+3IIiw4qM5hnMw= =s83f -----END PGP PRIVATE KEY BLOCK-----
Make sure to copy this string in its entirety.
(ref)
This is wrong and does not work - you need to remove the first and last header lines. See https://github.com/vanniktech/gradle-maven-publish-plugin/issues/819#issuecomment-2964582429 and the kdoc. This was exactly my experience when setting up publishing as well.
This is very hard to debug unless you get lucky and stumble across one of these sources. It would be a great help to new users if the docs were correct.