closure built after get is subject to stale context

[albertnetymk]

def id(x:int) : int
  x

class Test
  def f() : int
    0
  def g(f: int -> int) : void
    ()

class Main
  def main():void {
    repeat i <- 1000 {
      let t = new Test;
      get t.f();
      let f = \(x:int) -> id(x);
      t.g(f);
    }
  }

[supercooldave]

I don't really understand what this means.
What is the bug?
What error (message) is produced?

[kikofernandez]

@supercooldave the error message is:

Process 41948 launched: './error' (x86_64)
Assertion failed: (obj), function gc_sendobject, file libponyrt/gc/gc.c, line 165.

This is a bug in the tracing of the closure (I believe), which doesn't get a new context (pony_ctx()) after the call get. The error is produced when the Main actor gets blocked, is un-scheduled, gets fulfilled, and now a different pthread continues the execution. The context contains information about the current actor, scheduler, etc which is thread-local information. Since another pthread has resumed the actor, this information will not match whatever it was before. (this is my understanding of the issue)