Ignore pending_signals when checking for quits.

pending_signals is often set if no quit is pending.  This results in
bugs in module code if the module returns but no quit is actually
pending.

As a better alternative, add a new process_input environment function
for Emacs 27.  That function processes signals (like maybe_quit).

* configure.ac: Add module snippet for Emacs 27.

* src/module-env-27.h: New file.

* src/emacs-module.h.in: Add process_input function to environment
interface.

* src/emacs-module.c (module_should_quit): Use QUITP macro to check
whether the caller should quit.
(module_process_input): New function.
(initialize_environment): Use it.

* src/eval.c: Remove obsolete comment.

* test/data/emacs-module/mod-test.c (signal_wrong_type_argument)
(signal_errno): New helper functions.
(Fmod_test_sleep_until): New test module function.

* test/src/emacs-module-tests.el (mod-test-sleep-until): New unit
test.

* doc/lispref/internals.texi (Module Misc): Document process_input.

1 files changed, 20 insertions, 0 deletions

diff --git a/test/src/emacs-module-tests.el b/test/src/emacs-module-tests.el
index e4593044ecd..e30980b5993 100644
--- a/test/src/emacs-module-tests.el
+++ b/test/src/emacs-module-tests.el
@@ -289,4 +289,24 @@ Return A + B"
     (should (member '(provide . mod-test) entries))
     (should (member '(defun . mod-test-sum) entries))))
 
+(ert-deftest mod-test-sleep-until ()
+  "Check that `mod-test-sleep-until' either returns normally or quits.
+Interactively, you can try hitting \\[keyboard-quit] to quit."
+  (dolist (arg '(nil t))
+    ;; Guard against some caller setting `inhibit-quit'.
+    (with-local-quit
+      (condition-case nil
+          (should (eq (with-local-quit
+                        ;; Because `inhibit-quit' is nil here, the next
+                        ;; form either quits or returns `finished'.
+                        (mod-test-sleep-until
+                         ;; Interactively, run for 5 seconds to give the
+                         ;; user time to quit.  In batch mode, run only
+                         ;; briefly since the user can't quit.
+                         (float-time (time-add nil (if noninteractive 0.1 5)))
+                         ;; should_quit or process_input
+                         arg))
+                      'finished))
+        (quit)))))
+
 ;;; emacs-module-tests.el ends here