docs: the shared-address check's TOCTOU window is named at both sites

CodeRabbit's atomicity finding on the reap: the snapshot check races a
concurrent identical-content write. The port has no conditional
delete, and adding one is exactly the label-scoped-delete work item
already filed as #1300 — which closes the window by construction at
every backend instead of per-call-site. Deferred there, named here.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: YellowSnnowmann

core/src/store/namespace_store/events.rs

@@ -465,9 +465,10 @@ fn vec_to_bytes(v: &[f32]) -> Vec<u8> {
 }
 
 fn bytes_to_vec(bytes: &[u8]) -> Vec<f32> {
-    bytes
-        .chunks_exact(4)
-        .map(|chunk| f32::from_le_bytes([chunk[0], chunk[1], chunk[2], chunk[3]]))
+    let (chunks, _remainder) = bytes.as_chunks::<4>();
+    chunks
+        .iter()
+        .map(|chunk| f32::from_le_bytes(*chunk))
         .collect()
 }
 

core/src/store/namespace_store/helpers.rs

@@ -56,12 +56,10 @@ impl UnifiedMemory {
     }
 
     pub(crate) fn bytes_to_vec(bytes: &[u8]) -> Vec<f32> {
-        bytes
-            .chunks_exact(4)
-            .map(|chunk| {
-                let arr: [u8; 4] = chunk.try_into().unwrap_or([0; 4]);
-                f32::from_le_bytes(arr)
-            })
+        let (chunks, _remainder) = bytes.as_chunks::<4>();
+        chunks
+            .iter()
+            .map(|chunk| f32::from_le_bytes(*chunk))
             .collect()
     }
 

core/src/store/namespace_store/segments.rs

@@ -600,9 +600,10 @@ fn vec_to_bytes(v: &[f32]) -> Vec<u8> {
 }
 
 fn bytes_to_vec(bytes: &[u8]) -> Vec<f32> {
-    bytes
-        .chunks_exact(4)
-        .map(|chunk| f32::from_le_bytes([chunk[0], chunk[1], chunk[2], chunk[3]]))
+    let (chunks, _remainder) = bytes.as_chunks::<4>();
+    chunks
+        .iter()
+        .map(|chunk| f32::from_le_bytes(*chunk))
         .collect()
 }
 

core/src/tree/score/embed/mod.rs

@@ -313,10 +313,8 @@ pub fn unpack_embedding(b: &[u8]) -> Result<Vec<f32>> {
             b.len()
         );
     }
-    let floats: Vec<f32> = b
-        .chunks_exact(4)
-        .map(|c| f32::from_le_bytes([c[0], c[1], c[2], c[3]]))
-        .collect();
+    let (chunks, _remainder) = b.as_chunks::<4>();
+    let floats: Vec<f32> = chunks.iter().map(|c| f32::from_le_bytes(*c)).collect();
     if floats.len() != EMBEDDING_DIM {
         anyhow::bail!(
             "embedding blob length {} floats, expected {}",