Fix rare failures in 'window-default-font-height'

* lisp/window.el (window-default-font-height): Avoid signaling an
error when a client TTY frame happens to have an X-style 'display'
parameter.  (Bug#48408)

diff --git a/lisp/window.el b/lisp/window.el
index 1c719480cab57fa5b179f6ba4afc2b7f87771a36..0f94d8a2141894ad12799c8385e0799166d4fc6d 100644 (file)
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -8788,7 +8788,11 @@ font on WINDOW's frame."
   (let* ((window (window-normalize-window window t))
         (frame (window-frame window))
         (default-font (face-font 'default frame)))
-    (if (and (display-multi-font-p (frame-parameter frame 'display))
+    ;; Client frames can have the 'display' parameter set like for X
+    ;; frames, even though they are TTY frames, so make sure we won't
+    ;; be duped by that up front with 'framep'.
+    (if (and (not (eq (framep frame) t))
+             (display-multi-font-p (frame-parameter frame 'display))
             (not (string-equal (frame-parameter frame 'font) default-font)))
         (aref (font-info default-font frame) 3)
       (frame-char-height frame))))