Fix old string serializer (#4644)

openhands/core/config/llm_config.py

@@ -3,6 +3,7 @@ from dataclasses import dataclass, fields
 from typing import Optional
 
 from openhands.core.config.config_utils import get_field_info
+from openhands.core.logger import LOG_DIR
 
 LLM_SENSITIVE_FIELDS = ['api_key', 'aws_access_key_id', 'aws_secret_access_key']
 
@@ -74,7 +75,7 @@ class LLMConfig:
     disable_vision: bool | None = None
     caching_prompt: bool = True
     log_completions: bool = False
-    log_completions_folder: str | None = None
+    log_completions_folder: str = os.path.join(LOG_DIR, 'completions')
     draft_editor: Optional['LLMConfig'] = None
 
     def defaults_to_dict(self) -> dict:

openhands/core/config/utils.py

@@ -200,7 +200,9 @@ def finalize_config(cfg: AppConfig):
             parts = cfg.workspace_mount_rewrite.split(':')
             cfg.workspace_mount_path = base.replace(parts[0], parts[1])
 
+    # make sure log_completions_folder is an absolute path
     for llm in cfg.llms.values():
+        llm.log_completions_folder = os.path.abspath(llm.log_completions_folder)
         if llm.embedding_base_url is None:
             llm.embedding_base_url = llm.base_url
 

openhands/core/message.py

@@ -66,6 +66,21 @@ class Message(BaseModel):
 
     @model_serializer
     def serialize_model(self) -> dict:
+        # We need two kinds of serializations:
+        # - into a single string: for providers that don't support list of content items (e.g. no vision, no tool calls)
+        # - into a list of content items: the new APIs of providers with vision/prompt caching/tool calls
+        # NOTE: remove this when litellm or providers support the new API
+        if self.cache_enabled or self.vision_enabled or self.tool_call_id is not None:
+            return self._list_serializer()
+        return self._string_serializer()
+
+    def _string_serializer(self):
+        content = '\n'.join(
+            item.text for item in self.content if isinstance(item, TextContent)
+        )
+        return {'content': content, 'role': self.role}
+
+    def _list_serializer(self):
         content: list[dict] = []
         role_tool_with_prompt_caching = False
         for item in self.content:

tests/unit/test_message_serialization.py

@@ -78,10 +78,7 @@ def test_message_with_only_text_content_and_vision_disabled():
 
     expected_serialized_message = {
         'role': 'user',
-        'content': [
-            {'type': 'text', 'text': 'This is a text message'},
-            {'type': 'text', 'text': 'This is another text message'},
-        ],
+        'content': 'This is a text message\nThis is another text message',
     }
 
     assert serialized_message == expected_serialized_message
@@ -110,10 +107,7 @@ def test_message_with_mixed_content_and_vision_disabled():
     # Expected serialization ignores images and concatenates text
     expected_serialized_message = {
         'role': 'user',
-        'content': [
-            {'type': 'text', 'text': 'This is a text message'},
-            {'type': 'text', 'text': 'This is another text message'},
-        ],
+        'content': 'This is a text message\nThis is another text message',
     }
 
     # Assert serialized message matches expectation