griffinbank / griffinbank/rules_clojure
compile-time use of `construct-proxy`/`definterface` etc. doesn't work due to ClassLoader
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- Dominant language
- Clojure
- Stars
- 60
- Forks
- 13
- PR merge metrics
- No merged PRs in 30d
Description
Clojure assumes that clojure.lang.Compiler/LOADER is a DynamicClassLoader in a few places, but rules-clojure.persistentClassLoader is what's set to the ClassLoader instead. This causes the compilation step to fail. Compiling a namespace referencing a namespace containing (def foo (get-proxy-class ExceptionInfo)) should reproduce the error, with the message :cause class rules_clojure.persistentClassLoader cannot be cast to class clojure.lang.DynamicClassLoader (rules_clojure.persistentClassLoader is in unnamed module of loader 'app'; clojure.lang.DynamicClassLoader is in unnamed module of loader rules_clojure.persistentClassLoader @65ff29ae)
(note: for some reason I have to put that repro in b, and then compile a which :requires b)
~/src/github.com/clojure/clojure master*
❯ rg '\^.*DynamicClassLoader'
src/clj/clojure/genclass.clj
722: (.defineClass ^DynamicClassLoader (deref clojure.lang.Compiler/LOADER)
src/clj/clojure/repl/deps.clj
32: (.addURL ^DynamicClassLoader loader u)
src/clj/clojure/core_proxy.clj
293: (. ^DynamicClassLoader (deref clojure.lang.Compiler/LOADER) (defineClass pname bytecode [super interfaces]))))))
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Research direction
Start with the DynamicClassLoader uses in src/clj/clojure/genclass.clj, src/clj/clojure/repl/deps.clj, and src/clj/clojure/core_proxy.clj, then reproduce the failure by compiling namespace b containing the get-proxy-class form and compiling namespace a that requires b. Trace how rules_clojure.persistentClassLoader becomes Compiler/LOADER. Done means the compile-time proxy case no longer fails with the ClassLoader cast error.
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Assessment
- Tech stack
- clojure
- Domain
- build-system, compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100