Apply tooltip assertions to all instances of x-show-tip

* src/haikufns.c (Fx_show_tip):
(syms_of_haikufns):
* src/nsfns.m (Fx_show_tip):
(syms_of_nsfns):
* src/pgtkfns.c (Fx_show_tip):
(syms_of_pgtkfns):
* src/xfns.c (Fx_show_tip):
(syms_of_xfns): Add assertion and adjust default values.

1 files changed, 25 insertions, 2 deletions

diff --git a/src/pgtkfns.c b/src/pgtkfns.c
index 5c43e5f3607..d998c3d938c 100644
--- a/src/pgtkfns.c
+++ b/src/pgtkfns.c
@@ -3130,6 +3130,10 @@ Text larger than the specified size is clipped.  */)
   int old_windows_or_buffers_changed = windows_or_buffers_changed;
   specpdl_ref count = SPECPDL_INDEX ();
   Lisp_Object window, size, tip_buf;
+  bool displayed;
+#ifdef ENABLE_CHECKING
+  struct glyph_row *row, *end;
+#endif
   AUTO_STRING (tip, " *tip*");
 
   specbind (Qinhibit_redisplay, Qt);
@@ -3334,7 +3338,26 @@ Text larger than the specified size is clipped.  */)
   clear_glyph_matrix (w->desired_matrix);
   clear_glyph_matrix (w->current_matrix);
   SET_TEXT_POS (pos, BEGV, BEGV_BYTE);
-  try_window (window, pos, TRY_WINDOW_IGNORE_FONTS_CHANGE);
+  displayed = try_window (window, pos, TRY_WINDOW_IGNORE_FONTS_CHANGE);
+
+  if (!displayed && NILP (Vx_max_tooltip_size))
+    {
+#ifdef ENABLE_CHECKING
+      row = w->desired_matrix->rows;
+      end = w->desired_matrix->rows + w->desired_matrix->nrows;
+
+      while (row < end)
+        {
+          if (!row->displays_text_p
+              || row->ends_at_zv_p)
+            break;
+          ++row;
+        }
+
+      eassert (row < end && row->ends_at_zv_p);
+#endif
+    }
+
   /* Calculate size of tooltip window.  */
   size = Fwindow_text_pixel_size (window, Qnil, Qnil, Qnil,
                                   make_fixnum (w->pixel_height), Qnil,
@@ -3924,7 +3947,7 @@ syms_of_pgtkfns (void)
 
   DEFVAR_LISP ("x-max-tooltip-size", Vx_max_tooltip_size,
                doc: /* SKIP: real doc in xfns.c.  */);
-  Vx_max_tooltip_size = Fcons (make_fixnum (80), make_fixnum (40));
+  Vx_max_tooltip_size = Qnil;
 
   DEFSYM (Qmono, "mono");
   DEFSYM (Qassq_delete_all, "assq-delete-all");