2 files changed, 10 insertions, 8 deletions

diff --git a/lisp/window.el b/lisp/window.el
index 50aec86a427..4e72d343674 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -4278,7 +4278,7 @@ WINDOW must be a live window and defaults to the selected one."
                         (list (copy-marker start)
                               (copy-marker
                                ;; Preserve window-point-insertion-type
-                               ;; (Bug#12588).
+                               ;; (Bug#12855).
                                point window-point-insertion-type)))))
           (set-window-prev-buffers
            window (cons entry (window-prev-buffers window)))))
@@ -6110,7 +6110,7 @@ element is BUFFER."
          (list 'other
                ;; A quadruple of WINDOW's buffer, start, point and height.
                (list (current-buffer) (window-start window)
-                     ;; Preserve window-point-insertion-type (Bug#12588).
+                     ;; Preserve window-point-insertion-type (Bug#12855).
                      (copy-marker
                       (window-point window) window-point-insertion-type)
                      (if (window-combined-p window)
diff --git a/src/window.c b/src/window.c
index 14b3364477e..a69b115e4bb 100644
--- a/src/window.c
+++ b/src/window.c
@@ -6965,6 +6965,12 @@ save_window_save (Lisp_Object window, struct Lisp_Vector *vector, ptrdiff_t i)
 
       if (BUFFERP (w->contents))
         {
+          Lisp_Object buffer_local_window_point_insertion_type
+            = (buffer_local_value (Qwindow_point_insertion_type, w->contents));
+          bool window_point_insertion_type
+            = (!NILP (buffer_local_window_point_insertion_type)
+               && !EQ (buffer_local_window_point_insertion_type, Qunbound));
+
           /* Save w's value of point in the window configuration.  If w
              is the selected window, then get the value of point from
              the buffer; pointm is garbage in the selected window.  */
@@ -6975,12 +6981,8 @@ save_window_save (Lisp_Object window, struct Lisp_Vector *vector, ptrdiff_t i)
           else
             p->pointm = Fcopy_marker (w->pointm, Qnil);
           p->old_pointm = Fcopy_marker (w->old_pointm, Qnil);
-          XMARKER (p->pointm)->insertion_type
-            = !NILP (buffer_local_value /* Don't signal error if void.  */
-                     (Qwindow_point_insertion_type, w->contents));
-          XMARKER (p->old_pointm)->insertion_type
-            = !NILP (buffer_local_value /* Don't signal error if void.  */
-                     (Qwindow_point_insertion_type, w->contents));
+          XMARKER (p->pointm)->insertion_type = window_point_insertion_type;
+          XMARKER (p->old_pointm)->insertion_type = window_point_insertion_type;
 
           p->start = Fcopy_marker (w->start, Qnil);
           p->start_at_line_beg = w->start_at_line_beg ? Qt : Qnil;