[gnome-builder] code-index: check for NULL code indexer

[Christian Hergert <chergert src gnome org>]

commit 940c7fa8cf06dff23e6eed928358653f6f6d923b
Author: Christian Hergert <chergert redhat com>
Date:   Fri Sep 1 23:13:26 2017 -0700

    code-index: check for NULL code indexer
    
    Fixes CID 175137

 .../code-index/ide-code-index-symbol-resolver.c    |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/plugins/code-index/ide-code-index-symbol-resolver.c 
b/plugins/code-index/ide-code-index-symbol-resolver.c
index 9f6212b..03e3754 100644
--- a/plugins/code-index/ide-code-index-symbol-resolver.c
+++ b/plugins/code-index/ide-code-index-symbol-resolver.c
@@ -103,6 +103,17 @@ ide_code_index_symbol_resolver_lookup_symbol_async (IdeSymbolResolver   *resolve
   code_indexer = ide_code_index_service_get_code_indexer (service, file_name);
 
   task = g_task_new (self, cancellable, callback, user_data);
+  g_task_set_source_tag (task, ide_code_index_symbol_resolver_lookup_symbol_async);
+  g_task_set_priority (task, G_PRIORITY_LOW);
+
+  if (code_indexer == NULL)
+    {
+      g_task_return_new_error (task,
+                               G_IO_ERROR,
+                               G_IO_ERROR_NOT_SUPPORTED,
+                               "Failed to lcoate code indexer");
+      return;
+    }
 
   if (g_task_return_error_if_cancelled (task))
     return;