(adjust_window_trailing_edge): Don't break out of the loop

because there's no next window, if there are parallel windows.
Do break out when WINDOW is nil.

1 files changed, 16 insertions, 6 deletions

diff --git a/src/window.c b/src/window.c
index e0ea9beb211..6993f29e01d 100644
--- a/src/window.c
+++ b/src/window.c
@@ -4279,15 +4279,17 @@ adjust_window_trailing_edge (window, delta, horiz_flag)
     {
       Lisp_Object first_parallel = Qnil;
 
-      p = XWINDOW (window);
-      parent = p->parent;
-
-      if (NILP (XWINDOW (window)->next))
+      if (NILP (window))
         {
+          /* This can happen if WINDOW on the previous iteration was
+             at top level of the tree and we did not exit.  */
           Fset_window_configuration (old_config);
-          error ("No other window following this one");
+          error ("Specified window edge is fixed");
         }
 
+      p = XWINDOW (window);
+      parent = p->parent;
+
       /* See if this level has windows in parallel in the specified
          direction.  If so, set FIRST_PARALLEL to the first one.  */
       if (horiz_flag)
@@ -4301,6 +4303,14 @@ adjust_window_trailing_edge (window, delta, horiz_flag)
             first_parallel = XWINDOW (parent)->hchild;
         }
 
+      /* If this level's succession is in the desired dimension,
+         and this window is the last one, its trailing edge is fixed.  */
+      if (NILP (XWINDOW (window)->next) && NILP (first_parallel))
+        {
+          Fset_window_configuration (old_config);
+          error ("Specified window edge is fixed");
+        }
+
       /* Don't make this window too small.  */
       if (XINT (CURSIZE (window)) + delta
           < (horiz_flag ? window_min_width : window_min_height))
@@ -4324,7 +4334,7 @@ adjust_window_trailing_edge (window, delta, horiz_flag)
          we will fail and report an error, above.)  */
       if (NILP (first_parallel))
         {
-          if (!NILP (XWINDOW (window)->next))
+          if (!NILP (p->next))
             {
               /* This may happen for the minibuffer.  In that case
                  the window_deletion_count check below does not work.  */