Unbreak beginend(marks-test and beginend-narrowing-test

[aagon]

Hello !

The tests in the files test/beginend-narrowing-test.el and test/beginend-marks-test.el can fail under a specific set of conditions.

Emacs 28 has introduced native compilation of elisp code. In order to allow the advising of primitives (functions accessible from elisp implemented in C) to benefit from native compilation as well, these primitives have to be replaced by a trampoline that allows jumping to arbitrary native code (that we imagine to be the native compiled version of the elisp function the user has replaced the primitive with).

The test bed provided by the two aforementioned files advises the primitive message :

  (before-each
    (spy-on 'message)) ;; disable "Mark activated/Mark set" messages

If no trampoline is already present for the primitive at the time of evaluation of the form, a trampoline has to be compiled from it. This trampoline compilation fails with the following backtrace :

Traceback (most recent call last):
  normal-top-level()
  command-line()
  command-line-1(("-L" "." "-l" "buttercup" "-f" "buttercup-run-discover" "-...
  buttercup-run-discover()
  buttercup-run()
  buttercup--run-suites((#s(buttercup-suite "beginend in a dired buffer" nil...
  mapc(buttercup--run-suite (#s(buttercup-suite "beginend in a dired buffer"...
  buttercup--run-suite(#s(buttercup-suite "beginend" nil passed nil nil (255...
  buttercup--run-suite(#s(buttercup-suite "pushes mark" #s(buttercup-suite "...
  buttercup--run-suite(#s(buttercup-suite "when going to beginning" #s(butte...
  buttercup--run-spec(#s(buttercup-spec "if point is not at beginning" #s(bu...
  buttercup--update-with-funcall(#s(buttercup-spec "if point is not at begin...
  apply(buttercup--funcall (closure (t) nil (spy-on 'message)) nil)
  buttercup--funcall((closure (t) nil (spy-on 'message)))
  apply((closure (t) nil (spy-on 'message)) nil)
  (closure (t) nil (spy-on 'message))()
  spy-on(message)
  buttercup--spy-on-and-call-replacement(message (lambda (&rest args) nil nil))
  comp-subr-trampoline-install(message)
  comp-trampoline-compile(message)
  comp--native-compile((lambda (arg0 &rest arg1) (let ((f #'message)) (apply...
  signal(file-missing ((lambda (arg0 &rest arg1) (let ((f #'message)) (apply...
error: (file-missing (lambda (arg0 &rest arg1) (let ((f #'message)) (apply f arg0 arg1))) "Setting current directory" "No such file or directory" "/tmp/temp-fs-dGkO0V")

You probably never reach this error because you are lucky to always have the trampoline already. In specific build environments, where tests are run in a clean environment with a clean emacs (for instance the Debian build process of beginend from which the backtrace is taken), the trampoline is not there and needs to be compiled. You should be able to reproduce if you delete the trampoline (it should be named something like subr-message-<some hash>.eln) before launching the test.

We have no idea why the function comp--native-compile errors. We do know that we can simply work around the error by deactivating trampoline compilation for this primitive, thus allowing the tests to pass.

This patch does exactly that.

Let me know if you have any questions.

Best,

Aymeric Agon-Rambosson

[DamienCassou]

Thank you very much for investigating the problem, providing a solution and explaining it to me. I really appreciate the effort!

Would you mind copy/pasting your explanation into the commit message so we keep a trace?

Thank you again!

[aagon]

Sorry for the late answer !

Would you mind copy/pasting your explanation into the commit message so we keep a trace?

Done !

[DamienCassou]

Great job!