Add test for lp#1760827 [was: Policy for adding marked-as-failing tests (= without a fix)?]

Andreas Franke via Sbcl-devel <[email protected]> Sat, 31 Jan 2026 05:03:02 +0000

Newsgroups	gmane.lisp.steel-bank.devel
Message-ID	<trinity-fb8c88eb-9c81-41d0-bfb1-9e1e5bf06635-1769835782374@trinity-msg-rest-gmx-gmx-live-6fb44d8b58-jlhrg>

Could we make a decision here please?
- Is lp#1760827 a valid issue?
- Can we add a failing test already, so as to inspire 
  some confidence that it is somehow possible to 
  create a fix that will be acceptable for merging?
  (See attachment for an example test.)

> [...] policy [for] when a new
> test pointing out a problem/limitation/flaw/issue in sbcl 
> may be considered acceptable for merging?
> 
> Naively, I had assumed that under almost any circumstance,
> having a marked-as-failing new test in-tree is strictly 
> better than not having it [...]

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condition-wait.impure.lisp (text/x-common-lisp, 1.8 KB)

;;;; tests for condition-wait timeout behavior

;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; While most of SBCL is derived from the CMU CL system, the test
;;;; files (like this one) were written from scratch after the fork
;;;; from CMU CL.
;;;;
;;;; This software is in the public domain and is provided with
;;;; absolutely no warranty. See the COPYING and CREDITS files for
;;;; more information.

(require :sb-concurrency)

(with-test (:name (:wait-on-gate :timeout))
  (let* ((gate (sb-concurrency:make-gate))
         (elapsed nil)
         (thread (sb-thread:make-thread
                   (lambda ()
                     (let ((start (get-internal-real-time)))
                       (sb-concurrency:wait-on-gate gate :timeout 0.5)
                       (setf elapsed (/ (- (get-internal-real-time) start)
                                        internal-time-units-per-second)))))))
    (sb-thread:join-thread thread :timeout 5)
    (assert (<= 0.3 elapsed 1.0))))

(with-test (:name (:wait-on-gate :timeout :with-gc)
            :fails-on :sbcl)
  ;; Bug #1760827: timeout may never occur with frequent GC interrupts.
  (let* ((gate (sb-concurrency:make-gate))
         (deadline-hit nil)
         (thread (sb-thread:make-thread
                   (lambda ()
                     (sb-concurrency:wait-on-gate gate :timeout 1.0)))))
    (handler-case
        (sb-sys:with-deadline (:seconds 5)
          (loop while (sb-thread:thread-alive-p thread)
                do (sb-ext:gc)
                   (sleep 0.5)))
      (sb-sys:deadline-timeout ()
        (setf deadline-hit t)))
    (sb-thread:join-thread thread :timeout 10)
    (assert (not deadline-hit) ()
            "Wait-on-gate did not complete within 5 seconds (bug #1760827)")))