Merge pull request #1 from tjni/vb/handle-null-chars

checkpoint-mysql: handle null chars in metadata

langgraph/checkpoint/mysql/base.py

@@ -231,7 +231,8 @@ def _load_metadata(self, metadata: str) -> CheckpointMetadata:
 
     def _dump_metadata(self, metadata: CheckpointMetadata) -> str:
         serialized_metadata = self.jsonplus_serde.dumps(metadata)
-        return serialized_metadata.decode()
+        # NOTE: we're using JSON serializer (not msgpack), so we need to remove null characters before writing
+        return serialized_metadata.decode().replace("\\u0000", "")
 
     def get_next_version(self, current: Optional[str], channel: ChannelProtocol) -> str:
         if current is None:

tests/test_async.py

@@ -104,6 +104,16 @@ async def test_asearch(self) -> None:
 
             # TODO: test before and limit params
 
+    async def test_null_chars(self) -> None:
+        async with AIOMySQLSaver.from_conn_string(DEFAULT_URI) as saver:
+            config = await saver.aput(
+                self.config_1, self.chkpnt_1, {"my_key": "\x00abc"}, {}
+            )
+            assert (await saver.aget_tuple(config)).metadata["my_key"] == "abc"
+            assert [c async for c in saver.alist(None, filter={"my_key": "abc"})][
+                0
+            ].metadata["my_key"] == "abc"
+
     async def test_write_and_read_pending_writes_and_sends(self) -> None:
         async with AIOMySQLSaver.from_conn_string(DEFAULT_URI) as saver:
             config: RunnableConfig = {

tests/test_sync.py

@@ -104,6 +104,15 @@ def test_search(self) -> None:
 
             # TODO: test before and limit params
 
+    def test_null_chars(self) -> None:
+        with PyMySQLSaver.from_conn_string(DEFAULT_URI) as saver:
+            config = saver.put(self.config_1, self.chkpnt_1, {"my_key": "\x00abc"}, {})
+            assert saver.get_tuple(config).metadata["my_key"] == "abc"
+            assert (
+                list(saver.list(None, filter={"my_key": "abc"}))[0].metadata["my_key"]
+                == "abc"
+            )
+
     def test_write_and_read_pending_writes_and_sends(self) -> None:
         with PyMySQLSaver.from_conn_string(DEFAULT_URI) as saver:
             config: RunnableConfig = {