Handle unterminated escape character when parsing partial JSON

libs/core/langchain_core/utils/json.py

@@ -95,6 +95,8 @@ def parse_partial_json(s: str, *, strict: bool = False) -> Any:
     # If we're still inside a string at the end of processing,
     # we need to close the string.
     if is_inside_string:
+        if escaped:  # Remoe unterminated escape character
+            new_chars.pop()
         new_chars.append('"')
 
     # Reverse the stack to get the closing characters.

libs/core/tests/unit_tests/output_parsers/test_json.py

@@ -242,6 +242,7 @@ def test_parse_json_with_python_dict() -> None:
     ('{"foo": "bar", "bar":', '{"foo": "bar"}'),
     ('{"foo": "bar", "bar"', '{"foo": "bar"}'),
     ('{"foo": "bar", ', '{"foo": "bar"}'),
+    ('{"foo":"bar\\', '{"foo": "bar"}'),
 ]