fixed sequence of multiple AIMessage (langchain-ai#335)

libs/vertexai/langchain_google_vertexai/chat_models.py

@@ -296,6 +296,14 @@ def _convert_to_parts(message: BaseMessage) -> List[Part]:
                 )
                 parts.append(Part(function_call=function_call))
 
+            prev_content = vertex_messages[-1]
+            prev_content_is_model = prev_content and prev_content.role == "model"
+            if prev_content_is_model:
+                prev_parts = list(prev_content.parts)
+                prev_parts.extend(parts)
+                vertex_messages[-1] = Content(role=role, parts=prev_parts)
+                continue
+
             vertex_messages.append(Content(role=role, parts=parts))
         elif isinstance(message, FunctionMessage):
             prev_ai_message = None
@@ -306,18 +314,18 @@ def _convert_to_parts(message: BaseMessage) -> List[Part]:
                     name=message.name, response={"content": message.content}
                 )
             )
+            parts = [part]
 
             prev_content = vertex_messages[-1]
             prev_content_is_function = prev_content and prev_content.role == "function"
+
             if prev_content_is_function:
-                parts = list(prev_content.parts)
-                parts.append(part)
+                prev_parts = list(prev_content.parts)
+                prev_parts.extend(parts)
                 # replacing last message
-                vertex_messages[-1] = Content(role=role, parts=parts)
+                vertex_messages[-1] = Content(role=role, parts=prev_parts)
                 continue
 
-            parts = [part]
-
             vertex_messages.append(Content(role=role, parts=parts))
         elif isinstance(message, ToolMessage):
             role = "function"
@@ -383,18 +391,19 @@ def _parse_content(raw_content: str | Dict[Any, Any]) -> Dict[Any, Any]:
                     response=content,
                 )
             )
+            parts = [part]
 
             prev_content = vertex_messages[-1]
             prev_content_is_function = prev_content and prev_content.role == "function"
+
             if prev_content_is_function:
-                parts = list(prev_content.parts)
-                parts.append(part)
+                prev_parts = list(prev_content.parts)
+                prev_parts.extend(parts)
                 # replacing last message
-                vertex_messages[-1] = Content(role=role, parts=parts)
+                vertex_messages[-1] = Content(role=role, parts=prev_parts)
                 continue
-            else:
-                parts = [part]
-                vertex_messages.append(Content(role=role, parts=parts))
+
+            vertex_messages.append(Content(role=role, parts=parts))
         else:
             raise ValueError(
                 f"Unexpected message with type {type(message)} at the position {i}."

libs/vertexai/langchain_google_vertexai/functions_utils.py

@@ -167,6 +167,12 @@ def _format_to_gapic_function_declaration(
     elif isinstance(tool, vertexai.FunctionDeclaration):
         return _format_vertex_to_function_declaration(tool)
     elif isinstance(tool, dict):
+        # this could come from
+        # 'langchain_core.utils.function_calling.convert_to_openai_tool'
+        if tool.get("type") == "function" and tool.get("function"):
+            return _format_dict_to_function_declaration(
+                cast(FunctionDescription, tool.get("function"))
+            )
         return _format_dict_to_function_declaration(tool)
     else:
         raise ValueError(f"Unsupported tool call type {tool}")

libs/vertexai/tests/unit_tests/test_chat_models.py

@@ -464,6 +464,51 @@ def test_parse_history_gemini_function() -> None:
                 )
             ],
         ),
+        (
+            [
+                AIMessage(
+                    content=["Mike age is 30"],
+                    tool_calls=[
+                        ToolCall(
+                            name="Information",
+                            args={"name": "Rob"},
+                            id="00000000-0000-0000-0000-00000000000",
+                        ),
+                    ],
+                ),
+                AIMessage(
+                    content=["Arthur age is 30"],
+                    tool_calls=[
+                        ToolCall(
+                            name="Information",
+                            args={"name": "Ben"},
+                            id="00000000-0000-0000-0000-00000000000",
+                        ),
+                    ],
+                ),
+            ],
+            [
+                Content(
+                    role="model",
+                    parts=[
+                        Part(text="Mike age is 30"),
+                        Part(
+                            function_call=FunctionCall(
+                                name="Information",
+                                args={"name": "Rob"},
+                            )
+                        ),
+                        Part(text="Arthur age is 30"),
+                        Part(
+                            function_call=FunctionCall(
+                                name="Information",
+                                args={"name": "Ben"},
+                            )
+                        ),
+                    ],
+                )
+            ],
+        ),
     ],
 )
 def test_parse_history_gemini_multi(source_history, expected_history) -> None: