core[patch]: Fixes for convert_messages (#21207)

- support two-tuples of any sequence type (eg. json.loads never produces
tuples)
- support type alias for role key
- if id is passed in in dict form use it
- if tool_calls passed in in dict form use them

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

.github/workflows/_lint.yml

@@ -44,7 +44,7 @@ jobs:
           python-version: ${{ matrix.python-version }}
           poetry-version: ${{ env.POETRY_VERSION }}
           working-directory: ${{ inputs.working-directory }}
-          cache-key: lint-with-extras
+#          cache-key: lint-with-extras
 
       - name: Check Poetry File
         shell: bash
@@ -79,14 +79,14 @@ jobs:
         run: |
           poetry run pip install -e "$LANGCHAIN_LOCATION"
 
-      - name: Get .mypy_cache to speed up mypy
-        uses: actions/cache@v4
-        env:
-          SEGMENT_DOWNLOAD_TIMEOUT_MIN: "2"
-        with:
-          path: |
-            ${{ env.WORKDIR }}/.mypy_cache
-          key: mypy-lint-${{ runner.os }}-${{ runner.arch }}-py${{ matrix.python-version }}-${{ inputs.working-directory }}-${{ hashFiles(format('{0}/poetry.lock', inputs.working-directory)) }}
+#      - name: Get .mypy_cache to speed up mypy
+#        uses: actions/cache@v4
+#        env:
+#          SEGMENT_DOWNLOAD_TIMEOUT_MIN: "2"
+#        with:
+#          path: |
+#            ${{ env.WORKDIR }}/.mypy_cache
+#          key: mypy-lint-${{ runner.os }}-${{ runner.arch }}-py${{ matrix.python-version }}-${{ inputs.working-directory }}-${{ hashFiles(format('{0}/poetry.lock', inputs.working-directory)) }}
 
 
       - name: Analysing the code with our lint
@@ -113,14 +113,14 @@ jobs:
         run: |
           poetry install --with test,test_integration
 
-      - name: Get .mypy_cache_test to speed up mypy
-        uses: actions/cache@v4
-        env:
-          SEGMENT_DOWNLOAD_TIMEOUT_MIN: "2"
-        with:
-          path: |
-            ${{ env.WORKDIR }}/.mypy_cache_test
-          key: mypy-test-${{ runner.os }}-${{ runner.arch }}-py${{ matrix.python-version }}-${{ inputs.working-directory }}-${{ hashFiles(format('{0}/poetry.lock', inputs.working-directory)) }}
+#      - name: Get .mypy_cache_test to speed up mypy
+#        uses: actions/cache@v4
+#        env:
+#          SEGMENT_DOWNLOAD_TIMEOUT_MIN: "2"
+#        with:
+#          path: |
+#            ${{ env.WORKDIR }}/.mypy_cache_test
+#          key: mypy-test-${{ runner.os }}-${{ runner.arch }}-py${{ matrix.python-version }}-${{ inputs.working-directory }}-${{ hashFiles(format('{0}/poetry.lock', inputs.working-directory)) }}
 
       - name: Analysing the code with our lint
         working-directory: ${{ inputs.working-directory }}

libs/core/langchain_core/messages/utils.py

@@ -130,7 +130,9 @@ def message_chunk_to_message(chunk: BaseMessageChunk) -> BaseMessage:
     )
 
 
-MessageLikeRepresentation = Union[BaseMessage, Tuple[str, str], str, Dict[str, Any]]
+MessageLikeRepresentation = Union[
+    BaseMessage, List[str], Tuple[str, str], str, Dict[str, Any]
+]
 
 
 def _create_message_from_message_type(
@@ -138,6 +140,8 @@ def _create_message_from_message_type(
     content: str,
     name: Optional[str] = None,
     tool_call_id: Optional[str] = None,
+    tool_calls: Optional[List[Dict[str, Any]]] = None,
+    id: Optional[str] = None,
     **additional_kwargs: Any,
 ) -> BaseMessage:
     """Create a message from a message type and content string.
@@ -156,6 +160,10 @@ def _create_message_from_message_type(
         kwargs["tool_call_id"] = tool_call_id
     if additional_kwargs:
         kwargs["additional_kwargs"] = additional_kwargs  # type: ignore[assignment]
+    if id is not None:
+        kwargs["id"] = id
+    if tool_calls is not None:
+        kwargs["tool_calls"] = tool_calls
     if message_type in ("human", "user"):
         message: BaseMessage = HumanMessage(content=content, **kwargs)
     elif message_type in ("ai", "assistant"):
@@ -197,15 +205,17 @@ def _convert_to_message(
         _message = message
     elif isinstance(message, str):
         _message = _create_message_from_message_type("human", message)
-    elif isinstance(message, tuple):
-        if len(message) != 2:
-            raise ValueError(f"Expected 2-tuple of (role, template), got {message}")
-        message_type_str, template = message
+    elif isinstance(message, Sequence) and len(message) == 2:
+        # mypy doesn't realise this can't be a string given the previous branch
+        message_type_str, template = message  # type: ignore[misc]
         _message = _create_message_from_message_type(message_type_str, template)
     elif isinstance(message, dict):
         msg_kwargs = message.copy()
+        try:
             try:
                 msg_type = msg_kwargs.pop("role")
+            except KeyError:
+                msg_type = msg_kwargs.pop("type")
             msg_content = msg_kwargs.pop("content")
         except KeyError:
             raise ValueError(

libs/core/tests/unit_tests/test_messages.py

@@ -545,8 +545,8 @@ def test_convert_to_messages() -> None:
         [
             {"role": "system", "content": "You are a helpful assistant."},
             {"role": "user", "content": "Hello!"},
-            {"role": "ai", "content": "Hi!"},
-            {"role": "human", "content": "Hello!", "name": "Jane"},
+            {"role": "ai", "content": "Hi!", "id": "ai1"},
+            {"type": "human", "content": "Hello!", "name": "Jane", "id": "human1"},
             {
                 "role": "assistant",
                 "content": "Hi!",
@@ -554,13 +554,20 @@ def test_convert_to_messages() -> None:
                 "function_call": {"name": "greet", "arguments": '{"name": "Jane"}'},
             },
             {"role": "function", "name": "greet", "content": "Hi!"},
+            {
+                "role": "assistant",
+                "content": "",
+                "tool_calls": [
+                    {"name": "greet", "args": {"name": "Jane"}, "id": "tool_id"}
+                ],
+            },
             {"role": "tool", "tool_call_id": "tool_id", "content": "Hi!"},
         ]
     ) == [
         SystemMessage(content="You are a helpful assistant."),
         HumanMessage(content="Hello!"),
-        AIMessage(content="Hi!"),
-        HumanMessage(content="Hello!", name="Jane"),
+        AIMessage(content="Hi!", id="ai1"),
+        HumanMessage(content="Hello!", name="Jane", id="human1"),
         AIMessage(
             content="Hi!",
             name="JaneBot",
@@ -569,6 +576,10 @@ def test_convert_to_messages() -> None:
             },
         ),
         FunctionMessage(name="greet", content="Hi!"),
+        AIMessage(
+            content="",
+            tool_calls=[ToolCall(name="greet", args={"name": "Jane"}, id="tool_id")],
+        ),
         ToolMessage(tool_call_id="tool_id", content="Hi!"),
     ]
 
@@ -579,7 +590,7 @@ def test_convert_to_messages() -> None:
             "hello!",
             ("ai", "Hi!"),
             ("human", "Hello!"),
-            ("assistant", "Hi!"),
+            ["assistant", "Hi!"],
         ]
     ) == [
         SystemMessage(content="You are a helpful assistant."),