[gnome-builder] code-index: disable lookup_symbol when no project is loaded

[Christian Hergert <chergert src gnome org>]

commit 039c78ee8ae939e7b9c52d79a923de2c643526f8
Author: Christian Hergert <chergert redhat com>
Date:   Mon Feb 25 14:26:30 2019 -0800

    code-index: disable lookup_symbol when no project is loaded

 src/plugins/code-index/ide-code-index-symbol-resolver.c | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/src/plugins/code-index/ide-code-index-symbol-resolver.c 
b/src/plugins/code-index/ide-code-index-symbol-resolver.c
index cbe53b84e..358aceca9 100644
--- a/src/plugins/code-index/ide-code-index-symbol-resolver.c
+++ b/src/plugins/code-index/ide-code-index-symbol-resolver.c
@@ -159,6 +159,15 @@ ide_code_index_symbol_resolver_lookup_symbol_async (IdeSymbolResolver   *resolve
   context = ide_object_get_context (IDE_OBJECT (self));
   g_assert (IDE_IS_CONTEXT (context));
 
+  if (!ide_context_has_project (context))
+    {
+      ide_task_return_new_error (task,
+                                 G_IO_ERROR,
+                                 G_IO_ERROR_NOT_SUPPORTED,
+                                 "No project loaded, cannot use code-index");
+      return;
+    }
+
   service = gbp_code_index_service_from_context (context);
   g_assert (GBP_IS_CODE_INDEX_SERVICE (service));