The recursion seems to be between libsasl2-2 and libsasl2-modules. Manually installing those with dpkg -i /var/cache/apt/archives/libsals2* succeeds and allows Aptitude to continue the upgrade thereafter.
The recursion seems to be between libsasl2-2 and libsasl2-modules. Manually installing those with dpkg -i /var/cache/ apt/archives/ libsals2* succeeds and allows Aptitude to continue the upgrade thereafter.