From 7a264e870629f09fdfaed138cd80320841293be2 Mon Sep 17 00:00:00 2001
From: An Long <aisk1988@gmail.com>
Date: Tue, 8 Sep 2026 23:46:13 +0900
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20Return=20errors=20from=20binary?=
 =?UTF-8?q?=20prepend=20and=20map=20the=20NOT=5FSTORED=20status?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/error.rs           |  1 +
 src/protocol/binary.rs |  2 +-
 tests/tests.rs         | 15 +++++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/error.rs b/src/error.rs
index aab511a..add8109 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -125,6 +125,7 @@ impl From<u16> for CommandError {
             0x2 => CommandError::KeyExists,
             0x3 => CommandError::ValueTooLarge,
             0x4 => CommandError::InvalidArguments,
+            0x5 => CommandError::KeyNotFound,
             0x20 => CommandError::AuthenticationRequired,
             e => CommandError::Unknown(e),
         }
diff --git a/src/protocol/binary.rs b/src/protocol/binary.rs
index 1af0f0e..36de433 100644
--- a/src/protocol/binary.rs
+++ b/src/protocol/binary.rs
@@ -158,7 +158,7 @@ impl ProtocolTrait for BinaryProtocol {
         self.stream.write_all(key.as_bytes())?;
         value.write_to(&mut self.stream)?;
         self.stream.flush()?;
-        binary_packet::parse_response(&mut self.stream).map(|_| ())
+        binary_packet::parse_response(&mut self.stream)?.err().map(|_| ())
     }
 
     fn delete(&mut self, key: &str) -> Result<bool, MemcacheError> {
diff --git a/tests/tests.rs b/tests/tests.rs
index e1ffe5c..06845d7 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -113,6 +113,21 @@ fn udp_test() {
     let value: Option<String> = client.get("foo").unwrap();
     assert_eq!(value, None);
 
+    assert!(matches!(
+        client.append("foo", "bar"),
+        Err(memcache::MemcacheError::CommandError(
+            memcache::CommandError::KeyNotFound
+        ))
+    ));
+    assert!(matches!(
+        client.prepend("foo", "bar"),
+        Err(memcache::MemcacheError::CommandError(
+            memcache::CommandError::KeyNotFound
+        ))
+    ));
+    let value: Option<String> = client.get("foo").unwrap();
+    assert_eq!(value, None);
+
     client.add("foo", "bar", 0).unwrap();
     let value: Option<String> = client.get("foo").unwrap();
     assert_eq!(value, Some(String::from("bar")));