Fix handling double-click-time nil or t

* lisp/mouse.el (mouse-double-click-time): New function to always
return a number for `double-click-time'.
* lisp/emulation/viper-mous.el (viper-multiclick-timeout):
* lisp/foldout.el (foldout-mouse-swallow-events):
* lisp/help.el (help--read-key-sequence):
* lisp/org/org-mouse.el (org-mouse-show-context-menu): Use
'mouse-double-click-time' instead of 'double-click-time'.
* src/keyboard.c (syms_of_keyboard): Mention
'mouse-double-click-time' in doc string of 'double-click-time'.
* test/lisp/mouse-tests.el (mouse-test-mouse-double-click-time):
New test.

1 files changed, 14 insertions, 0 deletions

diff --git a/test/lisp/mouse-tests.el b/test/lisp/mouse-tests.el
index 1be32006a10..03ecbc19858 100644
--- a/test/lisp/mouse-tests.el
+++ b/test/lisp/mouse-tests.el
@@ -25,6 +25,20 @@
 
 ;;; Code:
 
+(ert-deftest mouse-test-mouse-double-click-time ()
+  (let ((double-click-time 500))
+    (should (= (mouse-double-click-time) 500)))
+  (let ((double-click-time 0))
+    (should (= (mouse-double-click-time) 0)))
+  (let ((double-click-time -500))
+    (should (= (mouse-double-click-time) 0)))
+  (let ((double-click-time nil))
+    (should (= (mouse-double-click-time) 0)))
+  (let ((double-click-time t))
+    (should (numberp (mouse-double-click-time))))
+  (let ((double-click-time '(invalid)))
+    (should (= (mouse-double-click-time) 0))))
+
 (ert-deftest bug23288-use-return-value ()
   "If `mouse-on-link-p' returns a string, its first character is used."
   (cl-letf ((unread-command-events '((down-mouse-1 nil 1) (mouse-1 nil 1)))