[asdf-devel] Alternate default lisp system location

[Daniel Herring]

On Wed, 12 Mar 2014, Faré wrote:

> Major changes like that happen less than once a year (ASDF 2 in 2010,
> ASDF 3 in 2013, ASDF 3.1 soon in 2014), and while
> backward-compatibility has always been a huge priority, improvements
> sometimes do mean the recommended way of using ASDF changes, for the
> better.

For essential infrastructure like what ASDF claims to be, I expect major 
changes to happen less than once every 5 to 10 years.  The more backwards 
compatibility, the better.  Projects like glibc have developed significant 
infrastructure to enable transparent improvements (see the ABI compliance 
checker, DSO symbol versioning, etc.).

Every breaking change inflicts cost on a fraction of the existing 
userbase, in exchange for some proposed benefit to future users.  Every 
time I have to debug breakage and change something or redesign my workflow 
to maintain existing capability, it encourages me to explore other, more 
stable or better designed options...

Sometimes "good ideas" fade after a month or two of reflection.  Some 
survive the test because the benefit truly outweighs the cost.  When that 
is the case, it is often helps to give the community time to prepare and 
minimize the number of times the community must change.  So propose the 
change, allow a long RFC window, allow users to obtain test 
implementations (while still promoting the stable branch), wait a while 
for several changes to collect before pushing them into major new 
releases, etc.

- Daniel