Fix some bugs in concat_byte_chunks, serialize_bsatn

crates/core/src/db/datastore/locking_tx_datastore/mod.rs

@@ -816,17 +816,12 @@ impl TxState {
     }
 }
 
-struct SequencesState {
+#[derive(Default)]
+pub struct SequencesState {
     sequences: HashMap<SequenceId, Sequence>,
 }
 
 impl SequencesState {
-    pub fn new() -> Self {
-        Self {
-            sequences: HashMap::new(),
-        }
-    }
-
     pub fn get_sequence_mut(&mut self, seq_id: SequenceId) -> Option<&mut Sequence> {
         self.sequences.get_mut(&seq_id)
     }
@@ -1832,7 +1827,7 @@ impl Locking {
         Self {
             memory: Arc::new(Mutex::new(BTreeMap::new())),
             committed_state: Arc::new(RwLock::new(CommittedState::new())),
-            sequence_state: Arc::new(Mutex::new(SequencesState::new())),
+            sequence_state: Arc::new(Mutex::new(SequencesState::default())),
             database_address,
         }
     }

crates/sats/src/algebraic_value/ser.rs

@@ -122,11 +122,16 @@ impl ser::Serializer for ValueSerializer {
 ///
 /// - `total_len == chunks.map(|c| c.len()).sum() <= isize::MAX`
 unsafe fn concat_byte_chunks<'a>(total_len: usize, chunks: impl Iterator<Item = &'a [u8]>) -> Vec<u8> {
+    if total_len == 0 {
+        return Vec::new();
+    }
+
     // Allocate space for `[u8; total_len]` on the heap.
     let layout = Layout::array::<u8>(total_len);
     // SAFETY: Caller promised that `total_len <= isize`.
     let layout = unsafe { layout.unwrap_unchecked() };
-    let ptr = alloc::alloc(layout);
+    // SAFETY: We checked above that `layout.size() != 0`.
+    let ptr = unsafe { alloc::alloc(layout) };
     if ptr.is_null() {
         alloc::handle_alloc_error(layout);
     }
@@ -157,7 +162,7 @@ unsafe fn concat_byte_chunks<'a>(total_len: usize, chunks: impl Iterator<Item =
     // - `total_len <= total_len` holds.
     // - `total_len` values were initialized at type `u8`
     //    as we know `total_len == chunks.map(|c| c.len()).sum()`.
-    Vec::from_raw_parts(ptr, total_len, total_len)
+    unsafe { Vec::from_raw_parts(ptr, total_len, total_len) }
 }
 
 /// Continuation for serializing an array.

crates/sats/src/bsatn/ser.rs

@@ -146,8 +146,8 @@ impl<W: BufWriter> ser::Serializer for Serializer<'_, W> {
         value.serialize(self)
     }
 
-    unsafe fn serialize_bsatn(self, ty: &crate::AlgebraicType, mut bsatn: &[u8]) -> Result<Self::Ok, Self::Error> {
-        debug_assert!(AlgebraicValue::decode(ty, &mut bsatn).is_ok());
+    unsafe fn serialize_bsatn(self, ty: &crate::AlgebraicType, bsatn: &[u8]) -> Result<Self::Ok, Self::Error> {
+        debug_assert!(AlgebraicValue::decode(ty, &mut { bsatn }).is_ok());
         self.writer.put_slice(bsatn);
         Ok(())
     }