Hi. Our current alternatives guidelines are very brief, but there are some examples with %post scriptlets.

I've followed the examples when creating alternatives for mercurial, but now I've discovered a bug:

https://bugzilla.redhat.com/show_bug.cgi?id=1831562

Running transaction Preparing : 1/1 Installing : mercurial-lang-5.2-4.fc32.x86_64 1/3 Installing : mercurial-py2-5.2-4.fc32.x86_64 2/3 Running scriptlet: mercurial-py2-5.2-4.fc32.x86_64 2/3 failed to link /usr/bin/hg -> /etc/alternatives/hg: /usr/bin/hg exists and it is not a symlink failed to link /usr/bin/hg-ssh -> /etc/alternatives/hg-ssh: /usr/bin/hg-ssh exists and it is not a symlink

Obsoleting : mercurial-4.9-2.fc31.x86_64 3/3 Running scriptlet: mercurial-4.9-2.fc31.x86_64 3/3 Verifying : mercurial-lang-5.2-4.fc32.x86_64 1/3 Verifying : mercurial-py2-5.2-4.fc32.x86_64 2/3 Verifying : mercurial-4.9-2.fc31.x86_64 3/3

Should the update-alternatives scriptlet be in %posttrans instead?