Re: warning about invalid tree model iterators

[Yevgen Muntyan <muntyan tamu edu>]

Tim Janik wrote:

> hi all.
>
> tree model iterators are easily advanced/setup/created in a way that 
> yields
> an invalid iterator, because the denoted location doesn't exist 
> (anymore).
> to cath those cases, the tree model API returns booleans indicating 
> success,
> but testing those booleans is easily forgotton and a common error source.
>
> to help the compiler catch these mistakes, i've prepared a patch that 
> adds
> G_GNUC_WARN_UNUSED_RESULT to all relevant iterator functions, and intend
> to commit that next week unless objections pop up. in principle it does:
> ...
>
> @@ -191,14 +191,14 @@ GType             gtk_tree_model_get_col
> /* Iterator movement */
> gboolean          gtk_tree_model_get_iter        (GtkTreeModel *tree_model,
> 						  GtkTreeIter  *iter,
> -						  GtkTreePath  *path);
> +						  GtkTreePath  *path) G_GNUC_WARN_UNUSED_RESULT;
>  
Here's code I have here:

GtkTreeRowReference *row = i_store_it_somewhere ();
if (gtk_tree_row_reference_valid (row))
{
      GtkTreePath *path = gtk_tree_row_reference_get_path (row);
      gtk_tree_model_get_iter (model, &iter, path);
      ...
}

Or I do

path = gtk_tree_row_reference_get_path (row);
if (path)
{
      /* it is valid */
      gtk_tree_model_get_iter (model, &iter, path);
      ...
}

In either case I have a valid path, and there's no need to heck return
value of gtk_tree_model_get_iter. This code is real code from my
application, I guess one could make up examples where warnings are
not needed for other cases too.

Best regards,
Yevgen