One great innovation of the original ASDF was its ability to leverage
CL:TRUENAME to locate where your source code was and where to build it,
allowing for symlink farms as a simple but effective configuration mechanism
that is easy to control programmatically.
ASDF 3 still supports this configuration style, and it is enabled by default;
however we recommend you instead use
our source-registry configuration mechanism described below,
because it is easier to setup in a portable way across users and implementations.
Additionally, some people dislike truename,
either because it is very slow on their system, or
because they are using content-addressed storage where the truename of a file
is related to a digest of its individual contents,
and not to other files in the same intended project.
For these people, ASDF 3 allows to eschew the
by setting the variable asdf:*resolve-symlinks* to
PS: Yes, if you haven’t read Vernor Vinge’s short but great classic “True Names... and Other Dangers” then you’re in for a treat.