[gtksourceview/wip/chergert/gsv-gtk4] completion: handle error cases better

[Christian Hergert <chergert src gnome org>]

commit 28dbec3ec3468ac971d7ccddf11d05399826f46e
Author: Christian Hergert <chergert redhat com>
Date:   Wed Sep 9 20:50:19 2020 -0700

    completion: handle error cases better

 gtksourceview/gtksourcecompletioncontext.c  |  3 +++
 gtksourceview/gtksourcecompletionprovider.c | 12 +++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)
---
diff --git a/gtksourceview/gtksourcecompletioncontext.c b/gtksourceview/gtksourcecompletioncontext.c
index 22e8d4bc..9a84d6c9 100644
--- a/gtksourceview/gtksourcecompletioncontext.c
+++ b/gtksourceview/gtksourcecompletioncontext.c
@@ -363,6 +363,9 @@ _gtk_source_completion_context_get_item_full (GtkSourceCompletionContext   *self
 
                n_items = g_list_model_get_n_items (info->results);
 
+               if (n_items == 0)
+                       continue;
+
                if (position >= n_items)
                {
                        position -= n_items;
diff --git a/gtksourceview/gtksourcecompletionprovider.c b/gtksourceview/gtksourcecompletionprovider.c
index 526e49cf..35a5cd6e 100644
--- a/gtksourceview/gtksourcecompletionprovider.c
+++ b/gtksourceview/gtksourcecompletionprovider.c
@@ -48,7 +48,17 @@ fallback_populate_async (GtkSourceCompletionProvider *provider,
 
        if (ret == NULL)
        {
-               g_task_return_error (task, g_steal_pointer (&error));
+               if (error != NULL)
+               {
+                       g_task_return_error (task, g_steal_pointer (&error));
+               }
+               else
+               {
+                       g_task_return_new_error (task,
+                                                G_IO_ERROR,
+                                                G_IO_ERROR_NOT_SUPPORTED,
+                                                "No results");
+               }
        }
        else
        {