[gtk/wip/carlosg/ignore-null-preedit] imcontextwayland: Ignore preedit updates from NULL to NULL

[Carlos Garnacho <carlosg src gnome org>]

commit d6fe6f495a52de47927bf17ce3bc492a971c025f
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Apr 26 12:23:09 2022 +0200

    imcontextwayland: Ignore preedit updates from NULL to NULL
    
    If we get consecutive preedit string updates that announce a NULL
    string, we still do end up issuing ::preedit-changed with those.
    Ignore changes from NULL to NULL, it is the other combinations which
    must issue this signal.

 gtk/gtkimcontextwayland.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gtk/gtkimcontextwayland.c b/gtk/gtkimcontextwayland.c
index ea9ed00cfc..069070509a 100644
--- a/gtk/gtkimcontextwayland.c
+++ b/gtk/gtkimcontextwayland.c
@@ -174,6 +174,9 @@ text_input_preedit_apply (GtkIMContextWaylandGlobal *global)
     return;
 
   context = GTK_IM_CONTEXT_WAYLAND (global->current);
+  if (context->pending_preedit.text == NULL &&
+      context->current_preedit.text == NULL)
+    return;
 
   state_change = ((context->pending_preedit.text == NULL)
                  != (context->current_preedit.text == NULL));