[tracker/tracker-1.8] libtracker-data: Return NULL SQL expression if the binding is not yet setup

[Carlos Garnacho <carlosg src gnome org>]

commit cc5b3c2f5f7e9721b29f29456e97922fb9fa29c7
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Nov 20 15:21:14 2016 +0100

    libtracker-data: Return NULL SQL expression if the binding is not yet setup
    
    Recent vala changed property setters so they compare with the previous
    value before emitting anything, this triggers the property getter called
    at a time when we just don't have a DataTable to construct the SQL
    expression (and it's being set anyway).
    
    So ensure the binding is in the right state before trying to construct a
    SQL expression for it.

 src/libtracker-data/tracker-sparql-query.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/libtracker-data/tracker-sparql-query.vala b/src/libtracker-data/tracker-sparql-query.vala
index 1b0842f..df3fc45 100644
--- a/src/libtracker-data/tracker-sparql-query.vala
+++ b/src/libtracker-data/tracker-sparql-query.vala
@@ -43,7 +43,7 @@ namespace Tracker.Sparql {
                public string sql_db_column_name;
                public string sql_expression {
                        get {
-                               if (this._sql_expression == null) {
+                               if (this._sql_expression == null && table != null) {
                                        this._sql_expression = "\"%s\".\"%s\"".printf 
(table.sql_query_tablename, sql_db_column_name);
                                }
                                return this._sql_expression;