Extension can hang if you halt

This example is stupid, but I wonder if it means there are other conditions under which the extension will hang.

I was curious if closing down and opening the extension had any memory leakage (it didn't as far as I could tell), so I ran

repeat 10000 [py:setup py:python3]

It took a long time, so I just halted it. I got the message below, and now I can't get the extension to py:setup again. Removing the extension, recompiling, adding it, and recompiling doesn't work. Running __reload_extensions also doesn't work.

NetLogo is unable to supply you with more details about this error.  Please report the problem 
 at https://github.com/NetLogo/NetLogo/issues, or to bugs@ccl.northwestern.edu, and paste the 
contents of this window into your report. 


java.lang.InterruptedException
 at java.lang.Object.wait(Native Method)
 at java.lang.UNIXProcess.waitFor(UNIXProcess.java:412)
 at org.nlogo.extensions.py.PythonSubprocess.close(PythonExtension.scala:481)
 at org.nlogo.extensions.py.PythonExtension$.$anonfun$pythonProcess_$eq$1(PythonExtension.scala:49)
 at org.nlogo.extensions.py.PythonExtension$.$anonfun$pythonProcess_$eq$1$adapted(PythonExtension.scala:49)
 at scala.Option.foreach(Option.scala:274)
 at org.nlogo.extensions.py.PythonExtension$.pythonProcess_$eq(PythonExtension.scala:49)
 at org.nlogo.extensions.py.SetupPython$.perform(PythonExtension.scala:549)
 at org.nlogo.prim._extern.perform(_extern.java:36)
 at org.nlogo.nvm.Context.stepConcurrent(Context.java:107)
 at org.nlogo.nvm.ConcurrentJob.step(ConcurrentJob.scala:65)
 at org.nlogo.job.JobThread.runPrimaryJobs(JobThread.scala:133)
 at org.nlogo.job.JobThread.$anonfun$run$1(JobThread.scala:68)
 at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
 at scala.util.control.Exception$Catch.apply(Exception.scala:228)
 at org.nlogo.api.Exceptions$.handling(Exceptions.scala:41)
 at org.nlogo.job.JobThread.run(JobThread.scala:66)

NetLogo 6.1.0
main: org.nlogo.app.AppFrame
thread: AWT-EventQueue-0
Java HotSpot(TM) 64-Bit Server VM 1.8.0_202 (Oracle Corporation; 1.8.0_202-b08)
operating system: Mac OS X 10.14.6 (x86_64 processor)
Scala version 2.12.8
JOGL: (3D View not initialized)
OpenGL Graphics: (3D View not initialized)
model: Untitled

01:12:41.017 AddJobEvent (org.nlogo.app.common.CommandLine) AWT-EventQueue-0
01:12:41.017 OutputEvent (org.nlogo.app.common.CommandLine) AWT-EventQueue-0
01:12:41.017 CompiledEvent (org.nlogo.window.CompilerManager) AWT-EventQueue-0
01:12:40.999 CompileMoreSourceEvent (org.nlogo.app.common.CommandLine) AWT-EventQueue-0
01:12:40.877 PeriodicUpdateEvent (org.nlogo.app.App$$anon$4 (org.nlogo.window.GUIWorkspace)) AWT-EventQueue-0
01:12:40.672 PeriodicUpdateEvent (org.nlogo.app.App$$anon$4 (org.nlogo.window.GUIWorkspace)) AWT-EventQueue-0
01:12:40.470 PeriodicUpdateEvent (org.nlogo.app.App$$anon$4 (org.nlogo.window.GUIWorkspace)) AWT-EventQueue-0
01:12:40.267 PeriodicUpdateEvent (org.nlogo.app.App$$anon$4 (org.nlogo.window.GUIWorkspace)) AWT-EventQueue-0
01:12:40.065 PeriodicUpdateEvent (org.nlogo.app.App$$anon$4 (org.nlogo.window.GUIWorkspace)) AWT-EventQueue-0
01:12:39.864 PeriodicUpdateEvent (org.nlogo.app.App$$anon$4 (org.nlogo.window.GUIWorkspace)) AWT-EventQueue-0

Bắt đầu với PythonExtension.scala, đặc biệt là PythonSubprocess.close và SetupPython.perform, sử dụng chuỗi lặp lại và dừng đã được báo cáo để tái hiện lỗi. Kiểm tra rằng sau khi dừng, py:setup và __reload_extensions hoạt động trở lại; stack trace và hành vi khôi phục không còn cho thấy extension bị mắc kẹt.