debug

topspace.el

@@ -268,7 +268,7 @@ Valid top space line heights are:
 - only positive when `window-start' equals 1,
   `topspace-active' returns non-nil, and `topspace-mode' is enabled,
 - not larger than `topspace--window-height' minus `topspace--context-lines'."
-  (interactive "p")
+  (interactive "P")
   (let ((old-height) (window (selected-window)))
     ;; Get the previous top space height
     (unless old-height (setq old-height (topspace-height)))
@@ -460,8 +460,9 @@ ARGS are needed for compatibility with `advice-add'."
 Will only set to HEIGHT if HEIGHT is a valid value as per
 `topspace--correct-height'.  This only sets the underlying stored value for
 top space height, and it does not redraw the top space."
-  (setf (alist-get (selected-window) topspace--heights)
-        (topspace--correct-height height)))
+  (setq height (topspace--correct-height height))
+  (setf (alist-get (selected-window) topspace--heights) height)
+  height)
 
 (defun topspace--correct-height (height)
   "Return HEIGHT if a valid top space line height, else a valid value.