reload-error-boot

Minimal repo for clojure-emacs/cider#2104.

This shows a problem with reloading the clojure.test.check.generators namespace without reloading the clojure.spec.gen.alpha namespace.

Since clojure.spec.gen.alpha doesn't :require clojure.test.check.generators, but rather dynamically loads some of its vars, the reload dependency tracking doesn't work properly.

Usage

1. cider-jack-in

2. Go to core.cljc and cider-eval-buffer, cider-refresh, etc.

   • See that generators for clojure.spec.gen.alpha and clojure.test.check.generators have the same classloaders:

   clojure.spec.alpha generator's classloader:  #object[clojure.lang.DynamicClassLoader 0x73867ca9 clojure.lang.DynamicClassLoader@73867ca9]
   clojure.test.check.generators generator's classloader:  #object[clojure.lang.DynamicClassLoader 0x73867ca9 clojure.lang.DynamicClassLoader@73867ca9]
   

3. In the REPL, compile ClojureScript with (boot (cljs))

4. C-u cider-refresh (refresh-all), then cider-eval-buffer again

   • See that the generators now have different classloaders:

   clojure.spec.alpha generator's classloader:  #object[clojure.lang.DynamicClassLoader 0x73867ca9 clojure.lang.DynamicClassLoader@73867ca9]
   clojure.test.check.generators generator's classloader:  #object[clojure.lang.DynamicClassLoader 0x170397bd clojure.lang.DynamicClassLoader@170397bd]
   

   In particular, that of clojure.test.check.generators has changed, while that of clojure.spec.gen.alpha ha remained the same. This is because clojure.test.check.generators was reloaded by the cider-refresh, thereby redefining the Generator record, but clojure.spec.gen.alpha was not.

   For more on records and classloaders, see Chris Houser's StackOverflow explanation.

5. Go to clojure/spec/gen/alpha.clj and eval the lazy-combinators form

   (lazy-combinators hash-map list map not-empty set vector vector-distinct fmap elements
                     bind choose fmap one-of such-that tuple sample return
                     large-integer* double* frequency)

6. cider-eval-buffer and see that clojure.spec.gen.alpha's generator now uses the clojure.test.check.generators's classloader again:

   clojure.spec.alpha generator's classloader:  #object[clojure.lang.DynamicClassLoader 0x170397bd clojure.lang.DynamicClassLoader@170397bd]
   clojure.test.check.generators generator's classloader:  #object[clojure.lang.DynamicClassLoader 0x170397bd clojure.lang.DynamicClassLoader@170397bd]
   

License

Copyright © 2017 Tianxiang Xiong

Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.