bug#47642: 28.0.50; (error "Selection owner couldn't convert" UTF8_STRING)

[Juri Linkov]

>> I wonder why this error should be raised at all
>> instead of just returning nil?
>
> That's a really good point -- this low-level error surely can't be of
> interest to the Emacs user.  So you're right -- it should just return
> nil here.

Here's the patch that does this:

diff --git a/src/xselect.c b/src/xselect.c
index 030f624071..cd6d86bdf4 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -1482,14 +1482,21 @@ x_get_window_property_as_lisp_data (struct 
x_display_info *dpyinfo,
        = XGetSelectionOwner (display, selection_atom) != 0;
       unblock_input ();
       if (there_is_a_selection_owner)
-       signal_error ("Selection owner couldn't convert",
-                     actual_type
-                     ? list2 (target_type,
-                              x_atom_to_symbol (dpyinfo, actual_type))
-                     : target_type);
+       {
+         AUTO_STRING (format, "Selection owner couldn't convert: %s");
+         CALLN (Fmessage, format,
+                actual_type
+                ? list2 (target_type,
+                         x_atom_to_symbol (dpyinfo, actual_type))
+                : target_type);
+         return Qnil;
+       }
       else
-       signal_error ("No selection",
-                     x_atom_to_symbol (dpyinfo, selection_atom));
+       {
+         AUTO_STRING (format, "No selection: %s");
+         CALLN (Fmessage, format, x_atom_to_symbol (dpyinfo, selection_atom));
+         return Qnil;
+       }
     }
 
   if (actual_type == dpyinfo->Xatom_INCR)