Fix tuple struct encoding in serde (#549)

Cargo.toml

@@ -42,6 +42,7 @@ criterion = "0.3"
 rand = "0.8"
 uuid = { version = "0.8", features = ["serde"] }
 chrono = { version = "0.4", features = ["serde"] }
+glam = { version="0.20.5", features=["serde"] }
 
 [[bench]]
 name = "varint"

compatibility/src/misc.rs

@@ -1,10 +1,17 @@
 #[test]
 fn test() {
     super::test_same((1,));
+    super::test_same(TupleS(2.0, 3.0, 4.0));
     super::test_same(Option::<u32>::Some(5));
     super::test_same(Option::<u32>::None);
     super::test_same(Result::<u32, u8>::Ok(5));
     super::test_same(Result::<u32, u8>::Err(5));
     super::test_same(std::net::Ipv4Addr::LOCALHOST);
     super::test_same(std::net::Ipv6Addr::LOCALHOST);
 }
+
+#[derive(
+    bincode_2::Encode, bincode_2::Decode, serde::Serialize, serde::Deserialize, Debug, PartialEq,
+)]
+#[bincode(crate = "bincode_2")]
+struct TupleS(f32, f32, f32);

src/features/serde/ser.rs

@@ -234,11 +234,10 @@ where
     }
 
     fn serialize_tuple_struct(
-        mut self,
+        self,
         _name: &'static str,
-        len: usize,
+        _len: usize,
     ) -> Result<Self::SerializeTupleStruct, Self::Error> {
-        len.encode(&mut self.enc)?;
         Ok(Compound { enc: self.enc })
     }
 

tests/issues.rs

@@ -23,3 +23,6 @@ mod issue_500;
 
 #[path = "issues/issue_523.rs"]
 mod issue_523;
+
+#[path = "issues/issue_547.rs"]
+mod issue_547;

tests/issues/issue_547.rs

@@ -0,0 +1,24 @@
+#![cfg(all(feature = "serde", feature = "std"))]
+
+use glam::vec3;
+
+use serde::{Deserialize, Serialize};
+
+#[derive(Serialize, Deserialize, Debug, PartialEq)]
+struct Instance {
+    position: glam::Vec3,
+}
+
+#[test]
+fn test() {
+    let instance = Instance {
+        position: vec3(2.0, 2.0, 2.0),
+    };
+
+    let m = bincode::serde::encode_to_vec(&instance, bincode::config::standard()).unwrap();
+    let instance2: Instance = bincode::serde::decode_from_slice(&m, bincode::config::standard())
+        .unwrap()
+        .0;
+
+    assert_eq!(instance, instance2);
+}

tests/serde.rs

@@ -10,28 +10,44 @@ pub struct SerdeRoundtrip {
     pub a: u32,
     #[serde(skip)]
     pub b: u32,
+    pub c: TupleS,
 }
 
+#[derive(Serialize, Deserialize, bincode::Encode, bincode::Decode, PartialEq, Debug)]
+pub struct TupleS(f32, f32, f32);
+
 #[test]
 fn test_serde_round_trip() {
     // validate serde attribute working
-    let json = serde_json::to_string(&SerdeRoundtrip { a: 5, b: 5 }).unwrap();
-    assert_eq!("{\"a\":5}", json);
+    let json = serde_json::to_string(&SerdeRoundtrip {
+        a: 5,
+        b: 5,
+        c: TupleS(2.0, 3.0, 4.0),
+    })
+    .unwrap();
+    assert_eq!("{\"a\":5,\"c\":[2.0,3.0,4.0]}", json);
 
     let result: SerdeRoundtrip = serde_json::from_str(&json).unwrap();
     assert_eq!(result.a, 5);
     assert_eq!(result.b, 0);
 
     // validate bincode working
-    let bytes =
-        bincode::encode_to_vec(SerdeRoundtrip { a: 15, b: 15 }, bincode::config::standard())
-            .unwrap();
-    assert_eq!(bytes, &[15, 15]);
+    let bytes = bincode::serde::encode_to_vec(
+        SerdeRoundtrip {
+            a: 15,
+            b: 15,
+            c: TupleS(2.0, 3.0, 4.0),
+        },
+        bincode::config::standard(),
+    )
+    .unwrap();
+    assert_eq!(bytes, &[15, 0, 0, 0, 64, 0, 0, 64, 64, 0, 0, 128, 64]);
     let (result, len): (SerdeRoundtrip, usize) =
-        bincode::decode_from_slice(&bytes, bincode::config::standard()).unwrap();
+        bincode::serde::decode_from_slice(&bytes, bincode::config::standard()).unwrap();
     assert_eq!(result.a, 15);
-    assert_eq!(result.b, 15);
-    assert_eq!(len, 2);
+    assert_eq!(result.b, 0); // remember: b is skipped
+    assert_eq!(result.c, TupleS(2.0, 3.0, 4.0));
+    assert_eq!(len, 13);
 }
 
 #[derive(Serialize, Deserialize, PartialEq, Debug)]

tests/utils.rs

@@ -27,20 +27,48 @@ where
     );
     assert_eq!(len, decoded_len);
 
-    #[cfg(all(feature = "serde", feature = "alloc"))]
-    // skip_fixed_array_length is not supposed on serde
+    #[cfg(feature = "serde")]
+    the_same_with_config_serde(element, config, cmp)
+}
+
+#[cfg(feature = "serde")]
+fn the_same_with_config_serde<V, C, CMP>(element: &V, config: C, cmp: CMP)
+where
+    V: TheSameTrait,
+    C: bincode::config::Config,
+    CMP: Fn(&V, &V) -> bool,
+{
+    use bincode::error::EncodeError;
+
+    let mut buffer = [0u8; 2048];
+    let len = bincode::serde::encode_into_slice(&element, &mut buffer, config);
+
+    let decoded = bincode::serde::decode_from_slice(&mut buffer, config);
+
     if !C::SKIP_FIXED_ARRAY_LENGTH {
-        let encoded = bincode::serde::encode_to_vec(&element, config).unwrap();
-        assert_eq!(&buffer[..len], &encoded);
-        let (decoded, decoded_len) = bincode::serde::decode_from_slice(&encoded, config).unwrap();
+        let len = len.unwrap();
+        let (decoded, decoded_len): (V, usize) = decoded.unwrap();
+        println!(
+            "{:?} ({}): {:?} ({:?})",
+            element,
+            core::any::type_name::<V>(),
+            &buffer[..len],
+            core::any::type_name::<C>()
+        );
+
         assert!(
             cmp(&element, &decoded),
             "Comparison failed\nDecoded:  {:?}\nExpected: {:?}\nBytes: {:?}",
             decoded,
             element,
             &buffer[..len],
         );
-        assert_eq!(decoded_len, len);
+        assert_eq!(len, decoded_len);
+    } else {
+        match len.unwrap_err() {
+            EncodeError::Serde(bincode::serde::EncodeError::SkipFixedArrayLengthNotSupported) => {}
+            err => panic!("Unexpected error: {:?}", err),
+        }
     }
 }