Interesting article (from 2014) about loading vars and Clojure boot time:
https://blog.ndk.io/solving-clojure-boot-time.html
Interestingly, making loading vars lazy could have negative consequences for GraalVM native-images. Since var loading involves class loading, this work must be done at image build time, hence the option --initialize-at-build-time is needed when producing native images. Luckily vars are initialized in static initializer blocks, so this work can in fact be done at image build time. Delaying this work to runtime will probably render Clojure native images completely unusable. I hope that any changes done to var loading will consider this scenario. Perhaps the old behavior can be preserved using a system property.
Yesterday I was discussing with @Chris_Nuernberger that the Clojure compiler (or some extra tool) could solve this “AOT” scenario in a different way. Perhaps it could emit some class loading code that could be ran “at build time” only for the vars needed in a final program, or the lazy loading (if that implementation is chosen) can be forced ahead of time for only the relevant vars, at build time.
For scenarios where startup time is important (short running scripts, AWS lambda) one could currently consider a GraalVM native-image based solution or babashka.