Fix int2vector serialization

postgres-types/src/lib.rs

@@ -910,9 +910,9 @@ impl<'a, T: ToSql> ToSql for &'a [T] {
             _ => panic!("expected array type"),
         };
 
-        // Arrays are normally one indexed by default but oidvector *requires* zero indexing
+        // Arrays are normally one indexed by default but oidvector and int2vector *require* zero indexing
         let lower_bound = match *ty {
-            Type::OID_VECTOR => 0,
+            Type::OID_VECTOR | Type::INT2_VECTOR => 0,
             _ => 1,
         };
 

tokio-postgres/tests/test/types/mod.rs

@@ -750,3 +750,14 @@ async fn oidvector() {
     )
     .await;
 }
+
+#[tokio::test]
+async fn int2vector() {
+    test_type(
+        "int2vector",
+        // NB: postgres does not support empty int2vectors! All empty arrays are normalized to zero dimensions, but the
+        // oidvectorrecv function requires exactly one dimension.
+        &[(Some(vec![0i16, 1, 2]), "ARRAY[0,1,2]"), (None, "NULL")],
+    )
+    .await;
+}