"java.net.BindException: Address already in use..." caused by orphaned java process

[jtcbrule]

I'm running lein-gorilla 0.3.1 on cygwin. Executing:

$ lein gorilla

from bash spawns a new bash process, which spawns a bash sub-process, which spawns a java subprocess, which spawns another java subprocess.

bash.exe (original, from which lein gorilla is executed)
bash.exe (new)
- bash.exe (subprocess)
- - java.exe
- - - java.exe

Ctrl+C kills the new bash.exe, the subprocess bash, and the first java.exe, but orphans the last java process.

This becomes a problem when trying to restart gorilla:

$ lein gorilla
Gorilla-REPL: 0.3.1
Started nREPL server on port 53008
Exception in thread "main" java.net.BindException: Address already in use: bind, compiling:(C:\cygwin\tmp\form-init8307404900158704503.clj:1:102)
        at clojure.lang.Compiler.load(Compiler.java:7142)
        at clojure.lang.Compiler.loadFile(Compiler.java:7086)
        at clojure.main$load_script.invoke(main.clj:274)
        at clojure.main$init_opt.invoke(main.clj:279)
        at clojure.main$initialize.invoke(main.clj:307)
        at clojure.main$null_opt.invoke(main.clj:342)
        at clojure.main$main.doInvoke(main.clj:420)
        at clojure.lang.RestFn.invoke(RestFn.java:421)
        at clojure.lang.Var.invoke(Var.java:383)
        at clojure.lang.AFn.applyToHelper(AFn.java:156)
        at clojure.lang.Var.applyTo(Var.java:700)
        at clojure.main.main(main.java:37)
Caused by: java.net.BindException: Address already in use: bind
        at sun.nio.ch.Net.bind0(Native Method)
        at sun.nio.ch.Net.bind(Unknown Source)
        at sun.nio.ch.Net.bind(Unknown Source)
        at sun.nio.ch.ServerSocketChannelImpl.bind(Unknown Source)
        at sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source)
        at sun.nio.ch.ServerSocketAdaptor.bind(Unknown Source)
        at org.httpkit.server.HttpServer.<init>(HttpServer.java:42)
        at org.httpkit.server$run_server.invoke(server.clj:8)
        at gorilla_repl.core$run_gorilla_server.invoke(core.clj:114)
        at user$eval3284.invoke(form-init8307404900158704503.clj:1)
        at clojure.lang.Compiler.eval(Compiler.java:6703)
        at clojure.lang.Compiler.eval(Compiler.java:6693)
        at clojure.lang.Compiler.load(Compiler.java:7130)
        ... 11 more

Manually killing the orphaned java.exe fixes this problem.

[JonyEpsilon]

Hmmm, that's not very good! I don't really know enough about how Leiningen spawns processes on Windows to even know how to begin fixing this, but I'll do a bit of Googling :-)

[jtcbrule]

A little more experimentation suggests that this is a leiningen/cygwin problem and not a gorilla problem; an ordinary "$ lein repl" invocation spawn the same tower of processes, and a Ctrl-C still orphans a java process.

I never noticed this since a) I almost always close a repl with Ctrl-D or (exit), and b) it's still possible to start a new repl without killing the orphaned java process