core[patch]: fix ChatGeneration.text with content blocks (langchain-a…

…i#20294)

libs/core/langchain_core/outputs/chat_generation.py

@@ -23,7 +23,24 @@ class ChatGeneration(Generation):
     def set_text(cls, values: Dict[str, Any]) -> Dict[str, Any]:
         """Set the text attribute to be the contents of the message."""
         try:
-            values["text"] = values["message"].content
+            text = ""
+            if isinstance(values["message"].content, str):
+                text = values["message"].content
+            # HACK: Assumes text in content blocks in OpenAI format.
+            # Uses first text block.
+            elif isinstance(values["message"].content, list):
+                for block in values["message"].content:
+                    if isinstance(block, str):
+                        text = block
+                        break
+                    elif isinstance(block, dict) and "text" in block:
+                        text = block["text"]
+                        break
+                    else:
+                        pass
+            else:
+                pass
+            values["text"] = text
         except (KeyError, AttributeError) as e:
             raise ValueError("Error while initializing ChatGeneration") from e
         return values

libs/core/tests/unit_tests/outputs/test_chat_generation.py

@@ -0,0 +1,32 @@
+from typing import Union
+
+import pytest
+
+from langchain_core.messages import AIMessage
+from langchain_core.outputs import ChatGeneration
+
+
+@pytest.mark.parametrize(
+    "content",
+    [
+        "foo",
+        ["foo"],
+        [{"text": "foo", "type": "text"}],
+        [
+            {"tool_use": {}, "type": "tool_use"},
+            {"text": "foo", "type": "text"},
+            "bar",
+        ],
+    ],
+)
+def test_msg_with_text(content: Union[str, list]) -> None:
+    expected = "foo"
+    actual = ChatGeneration(message=AIMessage(content=content)).text
+    assert actual == expected
+
+
+@pytest.mark.parametrize("content", [[], [{"tool_use": {}, "type": "tool_use"}]])
+def test_msg_no_text(content: Union[str, list]) -> None:
+    expected = ""
+    actual = ChatGeneration(message=AIMessage(content=content)).text
+    assert actual == expected