Treat an empty Statement.filters list as a scan instead of panicking

aerospike-core/src/client.rs

@@ -1960,7 +1960,7 @@ impl Client {
         }
 
         let task_id: u64 = rand::random();
-        let scan = statement.filters.is_none();
+        let scan = statement.filter().is_none();
 
         let mut last_err: Option<Error> = None;
         for node in &nodes {
@@ -2034,7 +2034,7 @@ impl Client {
         }
 
         let task_id: u64 = rand::random();
-        let scan = statement.filters.is_none();
+        let scan = statement.filter().is_none();
 
         let mut last_err: Option<Error> = None;
         for node in &nodes {

aerospike-core/src/commands/buffer.rs

@@ -1443,7 +1443,7 @@ impl Buffer {
         node_partitions: Option<&NodePartitions>,
         execute_where: Option<&[u8]>,
     ) -> Result<()> {
-        let filter = statement.filters.as_ref().map(|filters| &filters[0]);
+        let filter = statement.filter();
         let is_background = direction.is_background();
         let supports_ops_ext = node.version().supports_query_ops_projection_ext();
         let records_per_second = direction.records_per_second();

aerospike-core/src/commands/query_command.rs

@@ -97,7 +97,7 @@ impl Command for QueryCommand<'_> {
 
     fn command_type(&self) -> crate::metrics::CommandType {
         // A statement with secondary-index filters is a query; otherwise a scan.
-        if self.statement.filters.is_some() {
+        if self.statement.filter().is_some() {
             crate::metrics::CommandType::Query
         } else {
             crate::metrics::CommandType::Scan

aerospike-core/src/query/statement.rs

@@ -117,6 +117,12 @@ impl Statement {
         }
     }
 
+    /// The secondary-index filter this statement queries by, or `None` for a
+    /// scan. An empty `filters` list is a scan, the same as `None`.
+    pub(crate) fn filter(&self) -> Option<&Filter> {
+        self.filters.as_ref().and_then(|filters| filters.first())
+    }
+
     /// Set Lua aggregation function parameters.
     pub fn set_aggregate_function(
         &mut self,

tests/src/query.rs

@@ -178,6 +178,32 @@ async fn query_single_consumer() {
     client.close().await.unwrap();
 }
 
+#[aerospike_macro::test]
+async fn query_empty_filter_list_scans() {
+    let client = common::client().await;
+    let namespace = common::namespace();
+    let set_name = create_test_set(&client, 20).await;
+    let qpolicy = QueryPolicy::default();
+
+    let mut statement = Statement::new(namespace, &set_name, Bins::All);
+    statement.filters = Some(vec![]);
+    let rs = client
+        .query(&qpolicy, PartitionFilter::all(), statement)
+        .await
+        .unwrap();
+    let mut count = 0;
+    let mut rs = rs.into_stream();
+    while let Some(res) = rs.next().await {
+        match res {
+            Ok(_) => count += 1,
+            Err(err) => panic!("{:?}", err),
+        }
+    }
+    assert_eq!(count, 20);
+
+    client.close().await.unwrap();
+}
+
 #[aerospike_macro::test]
 async fn query_single_consumer_with_cursor() {
     let client = common::client().await;