bug#29272: 26.0.90; "C-h k C-mouse-3" followed by menu selection asks for more keys

[Noam Postavsky <npostavs@users.sourceforge.net>]

From what I can tell, we should only need to wait for a double click
when we get a single mouse event; when clicking in a menu,
read-key-sequence returns [(C-down-mouse-3 (#<window ...> ...)) the-command].  The following
works for me in lucid and gtk:

--- c/lisp/help.el
+++ i/lisp/help.el
@@ -726,19 +726,19 @@ help-read-key-sequence
           (while
               (pcase (setq key (read-key-sequence "\
 Describe the following key, mouse click, or menu item: "))
-                ((and (pred vectorp) (let `(,key0 . ,_) (aref key 0))
-                      (guard (symbolp key0)) (let keyname (symbol-name key0)))
-                 (or
-                  (and no-mouse-movement
-                       (string-match "mouse-movement" keyname))
-                  (and (string-match "\\(mouse\\|down\\|click\\|drag\\)"
-                                     keyname)
-                       (progn
-                         ;; Discard events (e.g. <help-echo>) which might
-                         ;; spuriously trigger the `sit-for'.
-                         (sleep-for 0.01)
-                         (while (read-event nil nil 0.01))
-                         (not (sit-for (/ double-click-time 1000.0) t))))))))
+                (`[(,key0 . ,_)]
+                 (or (and no-mouse-movement (eq key0 'mouse-movement))
+                     ;; Wait long enough to fully read a double click event.
+                     ;; FIXME: How to handle double-click-time = t?
+                     (and (numberp double-click-time)
+                          (string-match "\\(mouse\\|down\\|click\\|drag\\)"
+                                        (symbol-name key0))
+                          (progn
+                            ;; Discard events (e.g. <help-echo>) which might
+                            ;; spuriously trigger the `sit-for'.
+                            (sleep-for 0.01)
+                            (while (read-event nil nil 0.01))
+                            (not (sit-for (/ double-click-time 1000.0) t))))))))
           (list
            key
            ;; If KEY is a down-event, read and include the


martin rudalics <rudalics@gmx.at> writes:

> BTW: Could someone please fix that
>
> (not (sit-for (/ double-click-time 1000.0) t))
>
> form so it handles at least those values of `double-click-time'
> described in its documentation:
>
>   Maximum time between mouse clicks to make a double-click.
>   Measured in milliseconds.  The value nil means disable double-click
>   recognition; t means double-clicks have no time limit and are detected
>   by position only.
>
> I'm not sure what `sit-for' is supposed to return in those cases.

I don't know how to handle the double-click-time = t case though.