[racket-dev] [plt] Push #27825: master branch updated

From: Eli Barzilay (eli at barzilay.org)
Date: Mon Nov 25 05:02:07 EST 2013

IIUC, this makes the limit thing -- and therefore sandboxes -- behave
*very* differently.  The original intention was that the time limit is
on something similar to what you get with `time'.

A very visible way to see the effect of this change:

    -> ,r racket/sandbox
    -> (define e (make-evaluator 'racket))
    -> (e '(define foo 1))
    -> (e '(thread (lambda () (sleep 5) (set! foo 2))))

This used to happen immediately, with the thread continuing to run
inside the sandbox.  After your change, the last line hangs until the
thread is done.  Using a bigger sleeping time will make it throw an
error when it previously didn't.  Similarly,

    (make-module-evaluator "#lang racket (thread (λ() (sleep 99)))")

used to work and will throw an error now, and of course, any code that
runs some kind of sandboxed server will probably break now.

I think that instead of this, it'd be better to write a helper that
runs a thunk and waits for it and for any generated threads to end,
and suggest using this helper when you want to wait for all threads in
a `with-limits'.  (It might also be useful in the profiler, where a
similar kind of wait-for-all is done.)

On Friday, jay at racket-lang.org wrote:
> jay has updated `master' from e0026f5de4 to 79f8636e1e.
>   http://git.racket-lang.org/plt/e0026f5de4..79f8636e1e
> =====[ One Commit ]=====================================================
> Directory summary:
>   52.6% pkgs/racket-pkgs/racket-test/tests/racket/
>   45.6% pkgs/sandbox-lib/racket/
> ~~~~~~~~~~
> 79f8636 Jay McCarthy <jay at racket-lang.org> 2013-11-22 14:25
> :
> | Ensure that threads created within call-with-limits are accounted
> | during the time/space limits
> :
>   A pkgs/racket-pkgs/racket-test/tests/racket/sandbox.rkt
>   M pkgs/sandbox-lib/racket/sandbox.rkt               | 81 ++++++++++++++------
>   M .../racket-test/tests/racket/sandbox.rktl         | 48 ++++++++----
>   M .../scribblings/reference/sandbox.scrbl           |  4 +

          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!

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