diff --git a/core/src/layers/complete.rs b/core/src/layers/complete.rs
index e4488c6f177..0fe80f9bb50 100644
--- a/core/src/layers/complete.rs
+++ b/core/src/layers/complete.rs
@@ -670,7 +670,7 @@ impl<A> CompleteAppender<A> {
 #[cfg(debug_assertions)]
 impl<A> Drop for CompleteAppender<A> {
     fn drop(&mut self) {
-        if self.inner.is_none() {
+        if self.inner.is_some() {
             // Do we need to panic here?
             log::warn!("appender has not been closed, must be a bug")
         }
diff --git a/core/src/services/oss/backend.rs b/core/src/services/oss/backend.rs
index c436fc98314..64e78151391 100644
--- a/core/src/services/oss/backend.rs
+++ b/core/src/services/oss/backend.rs
@@ -49,6 +49,7 @@ const DEFAULT_WRITE_MIN_SIZE: usize = 8 * 1024 * 1024;
 /// - [x] stat
 /// - [x] read
 /// - [x] write
+/// - [x] append
 /// - [x] create_dir
 /// - [x] delete
 /// - [x] copy