From: Taylor R Campbell <campbell@mumble.net>
Date: Thu, 3 Jan 2019 16:33:31 +0000 (+0000)
Subject: Test detectable screw case of delay-force infinite recursion.
X-Git-Tag: mit-scheme-pucked-10.1.9~3^2~28
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=23704145f986dcbb9e5e271d50a5f81986244433;p=mit-scheme.git

Test detectable screw case of delay-force infinite recursion.
---

diff --git a/tests/runtime/test-promise.scm b/tests/runtime/test-promise.scm
index 703baba85..c8af319e7 100644
--- a/tests/runtime/test-promise.scm
+++ b/tests/runtime/test-promise.scm
@@ -28,6 +28,59 @@ USA.
 
 (declare (usual-integrations))
 
+(define (carefully procedure if-overflow if-timeout)
+  (let ((thread #f)
+        (mutex (make-thread-mutex))
+        (condvar (make-condition-variable))
+        (gc-env (->environment '(runtime garbage-collector))))
+    (define (start-it)
+      (with-thread-mutex-lock mutex
+        (lambda ()
+          (do () (thread)
+            (condition-variable-wait! condvar mutex))))
+      (let ((default/stack-overflow (access default/stack-overflow gc-env)))
+        (define (give-up)
+          (if (eq? thread (current-thread))
+              (exit-current-thread (if-overflow))
+              (default/stack-overflow)))
+        (call-with-current-continuation
+          (lambda (abort)
+            (fluid-let (((access hook/stack-overflow gc-env)
+                         (lambda () (within-continuation abort give-up))))
+              (exit-current-thread (procedure)))))))
+    (define (stop-it)
+      (assert thread)
+      (signal-thread-event thread
+                           (lambda ()
+                             (exit-current-thread (if-timeout)))))
+    (let ((t (create-thread #f start-it)))
+      (with-thread-mutex-lock mutex
+        (lambda ()
+          (set! thread t)
+          (condition-variable-broadcast! condvar))))
+    (let ((result #f))
+      (define (done-it thread* value)
+        (assert (eq? thread* thread))
+        (set! result value))
+      (join-thread thread done-it)
+      (let ((timer))
+        (dynamic-wind
+          (lambda () (set! timer (register-timer-event 1000 stop-it)))
+          (lambda () (do () (result) (suspend-current-thread)))
+          (lambda () (deregister-timer-event (set! timer))))))))
+
+(define-test 'delay-force-loop
+  (lambda ()
+    (expect-failure
+     (lambda ()
+       (assert-error
+        (lambda ()
+          (carefully (lambda ()
+                       (define p (delay-force p))
+                       (force p))
+                     (lambda () 'stack-overflow)
+                     (lambda () 'timeout))))))))
+
 (define-test 'force-force-delay-delay
   (lambda ()
     (assert-eqv (force (force (delay (delay 0)))) 0)))