fix: do not set peer id with max (#491)

crates/loro-common/src/error.rs

@@ -1,3 +1,5 @@
+use std::error;
+
 use serde_columnar::ColumnarError;
 use thiserror::Error;
 
@@ -90,6 +92,8 @@ pub enum LoroError {
         "The container {container} is deleted. You cannot apply the op on a deleted container."
     )]
     ContainerDeleted { container: Box<ContainerID> },
+    #[error("You cannot set the `PeerID` with `PeerID::MAX`, which is an internal specific value")]
+    InvalidPeerID,
 }
 
 #[derive(Error, Debug, PartialEq)]

crates/loro-internal/src/loro.rs

@@ -261,6 +261,9 @@ impl LoroDoc {
 
     #[inline(always)]
     pub fn set_peer_id(&self, peer: PeerID) -> LoroResult<()> {
+        if peer == PeerID::MAX {
+            return Err(LoroError::InvalidPeerID);
+        }
         let next_id = self.oplog.try_lock().unwrap().next_id(peer);
         if self.auto_commit.load(Acquire) {
             let doc_state = self.state.try_lock().unwrap();

crates/loro-internal/tests/test.rs

@@ -1,7 +1,7 @@
 use std::sync::{atomic::AtomicBool, Arc, Mutex};
 
 use fxhash::FxHashMap;
-use loro_common::{ContainerID, ContainerType, LoroResult, LoroValue, ID};
+use loro_common::{ContainerID, ContainerType, LoroError, LoroResult, LoroValue, PeerID, ID};
 use loro_internal::{
     delta::ResolvedMapValue,
     event::{Diff, EventTriggerKind},
@@ -1262,3 +1262,12 @@ fn test_map_contains_key() {
     map.delete("bro").unwrap();
     assert!(!map.contains_key("bro"));
 }
+
+#[test]
+fn set_max_peer_id() {
+    let doc = LoroDoc::new_auto_commit();
+    assert_eq!(
+        doc.set_peer_id(PeerID::MAX),
+        Result::Err(LoroError::InvalidPeerID)
+    );
+}