libtracker-miner: Warn when overwriting tasks in the task poolsam/tracker-miner-fs-test-fixes

The TrackerTaskPool class and its subclass TrackerSparqlBuffer are
designed to contain only one task for any given GFile.

If multiple tasks are pushed for the same file some of them might
not be executed. This leads to issues such as:
https://gitlab.gnome.org/GNOME/tracker/issues/15

1 files changed, 11 insertions, 0 deletions

diff --git a/src/libtracker-miner/tracker-task-pool.c b/src/libtracker-miner/tracker-task-pool.c
index f66d4b694..c17d961be 100644
--- a/src/libtracker-miner/tracker-task-pool.c
+++ b/src/libtracker-miner/tracker-task-pool.c
@@ -218,11 +218,22 @@ tracker_task_pool_add (TrackerTaskPool *pool,
                        TrackerTask     *task)
 {
 	TrackerTaskPoolPrivate *priv;
+	GFile *file;
 
 	g_return_if_fail (TRACKER_IS_TASK_POOL (pool));
 
 	priv = pool->priv;
 
+	file = tracker_task_get_file (task);
+
+	if (g_hash_table_contains (priv->tasks, file)) {
+		/* This is bad! We use the task's associated GFile as the key for the
+		 * hash table, so if there's already a value we are about to overwrite
+		 * it. This suggests there's a bug in the tracker-miner-fs.c code.
+		 */
+		g_warning ("Multiple update tasks for file %s", g_file_get_uri (file));
+	};
+
 	g_hash_table_insert (priv->tasks,
 	                     tracker_task_get_file (task),
 	                     tracker_task_ref (task));