[gimp] libgimp: improve gimp_procedure_dialog_check_mnemonic().

[Jehan <jehanp src gnome org>]

commit 929311f20874826ada4f76abe9a4ac6819caddfe
Author: Jehan <jehan girinstud io>
Date:   Wed Dec 30 13:31:16 2020 +0100

    libgimp: improve gimp_procedure_dialog_check_mnemonic().
    
    Use gtk_widget_list_mnemonic_labels() to look for mnemonic of common GTK
    widgets. Also warn when several mnemonic were set on a given widget
    ("wasting" keys when it seems we are always looking for available
    mnemonics).
    Also warn with core action IDs too when they miss a mnemonic.

 libgimp/gimpproceduredialog.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)
---
diff --git a/libgimp/gimpproceduredialog.c b/libgimp/gimpproceduredialog.c
index 20924295de..f0fa28e06d 100644
--- a/libgimp/gimpproceduredialog.c
+++ b/libgimp/gimpproceduredialog.c
@@ -1268,15 +1268,22 @@ gimp_procedure_dialog_check_mnemonic (GimpProcedureDialog *dialog,
     {
       label = gimp_labeled_get_label (GIMP_LABELED (widget));
     }
-  else if (g_type_is_a (G_OBJECT_TYPE (widget), GTK_TYPE_LABEL))
-    {
-      label = widget;
-    }
-  else if (g_type_is_a (G_OBJECT_TYPE (widget), GTK_TYPE_BUTTON))
+  else
     {
-      label = gtk_bin_get_child (GTK_BIN (widget));
-      if (! label || ! g_type_is_a (G_OBJECT_TYPE (label), GTK_TYPE_LABEL))
-        label = NULL;
+      GList *labels = gtk_widget_list_mnemonic_labels (widget);
+
+      if (g_list_length (labels) >= 1)
+        {
+          if (g_list_length (labels) > 1)
+            g_printerr ("Procedure '%s': %d mnemonics for property %s. Too much?\n",
+                        gimp_procedure_get_name (dialog->priv->procedure),
+                        g_list_length (labels),
+                        id ? id : core_id);
+
+          label = labels->data;
+        }
+
+      g_list_free (labels);
     }
 
   if (label                                                          &&
@@ -1314,7 +1321,8 @@ gimp_procedure_dialog_check_mnemonic (GimpProcedureDialog *dialog,
   else
     {
       g_printerr ("Procedure '%s': no mnemonic for property %s\n",
-                  gimp_procedure_get_name (dialog->priv->procedure), id);
+                  gimp_procedure_get_name (dialog->priv->procedure),
+                  id ? id : core_id);
       success = FALSE;
     }