From 50b09112b828d183838a4f027d0224c568e87f54 Mon Sep 17 00:00:00 2001
From: Ghraven <rollycalma13@gmail.com>
Date: Sun, 30 Aug 2026 19:18:19 +0800
Subject: [PATCH] fix(streamlit): read state logs as utf-8

---
 burr/integrations/streamlit.py       |  2 +-
 tests/integrations/test_streamlit.py | 65 ++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 tests/integrations/test_streamlit.py

diff --git a/burr/integrations/streamlit.py b/burr/integrations/streamlit.py
index 71b63bce0..c3b1df159 100644
--- a/burr/integrations/streamlit.py
+++ b/burr/integrations/streamlit.py
@@ -95,7 +95,7 @@ def load_state_from_log_file(jsonl_log_file: str, app: Application) -> AppState:
     :return: AppState
     """
     out = []
-    for i, line in enumerate(open(jsonl_log_file)):
+    for i, line in enumerate(open(jsonl_log_file, encoding="utf-8")):
         json_line = json.loads(line)
         record = Record(
             state=json_line["state"],
diff --git a/tests/integrations/test_streamlit.py b/tests/integrations/test_streamlit.py
new file mode 100644
index 000000000..122b0e689
--- /dev/null
+++ b/tests/integrations/test_streamlit.py
@@ -0,0 +1,65 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+import builtins
+import importlib
+import json
+import sys
+import types
+
+
+def test_load_state_from_log_file_reads_utf8(monkeypatch, tmp_path):
+    monkeypatch.setitem(
+        sys.modules,
+        "burr.integrations.hamilton",
+        types.SimpleNamespace(Hamilton=object, StateSource=object),
+    )
+    monkeypatch.setitem(sys.modules, "graphviz", types.SimpleNamespace(Digraph=object))
+    monkeypatch.setitem(
+        sys.modules, "streamlit", types.SimpleNamespace(session_state={})
+    )
+    streamlit = importlib.import_module("burr.integrations.streamlit")
+
+    log_file = tmp_path / "state.jsonl"
+    log_file.write_text(
+        json.dumps(
+            {
+                "state": {"message": "café"},
+                "action": "say",
+                "result": {"ok": True},
+            },
+            ensure_ascii=False,
+        )
+        + "\n",
+        encoding="utf-8",
+    )
+
+    real_open = builtins.open
+
+    def guarded_open(*args, **kwargs):
+        assert kwargs.get("encoding") == "utf-8"
+        return real_open(*args, **kwargs)
+
+    monkeypatch.setattr(builtins, "open", guarded_open)
+
+    app = object()
+    state = streamlit.load_state_from_log_file(str(log_file), app)
+
+    assert state.app is app
+    assert state.history[0].state == {"message": "café"}
+    assert state.history[0].action == "say"
+    assert state.history[0].result == {"ok": True}