Emily Shaffer [off-list ref] writes:

Basically, if this effort turns out not to be fruitful as a whole, I'd
like for us to still have left a positive impact on the codebase.
...
So what's next? Naturally, I'm looking forward to a spirited
discussion about this topic - I'd like to know which concerns haven't
been addressed and figure out whether we can find a way around them,
and generally build awareness of this effort with the community.

On of the gravest concerns is that the devil is in the details.

For example, "die() is inconvenient to callers, let's propagate
errors up the callchain" is an easy thing to say, but it would take
much more than "let's propagate errors up" to libify something like
check_connected() to do the same thing without spawning a separate
process that is expected to exit with failure.

It is not clear if we can start small, work on a subset of the
things and still reap the benefit of libification.  Is there an
existing example that we have successfully modularlized the API into
one subsystem?  Offhand, I suspect that the refs API with its two
implementations may be reasonably close, but is the inteface into
that subsystem the granularity of the library interface you guys
have in mind?