fix(langchain): silence intentional placeholder warnings

langfuse/model.py

@@ -308,6 +308,18 @@ def compile(
         Union[
             Dict[str, Any], ChatMessageDict, ChatMessageWithPlaceholdersDict_Placeholder
         ]
+    ]:
+        return self._compile(warn_on_unresolved_placeholders=True, **kwargs)
+
+    def _compile(
+        self,
+        *,
+        warn_on_unresolved_placeholders: bool,
+        **kwargs: Union[str, Any],
+    ) -> Sequence[
+        Union[
+            Dict[str, Any], ChatMessageDict, ChatMessageWithPlaceholdersDict_Placeholder
+        ]
     ]:
         """Compile the prompt with placeholders and variables.
 
@@ -381,7 +393,7 @@ def compile(
                     compiled_messages.append(chat_message)
                     unresolved_placeholders.append(chat_message["name"])  # type: ignore
 
-        if unresolved_placeholders:
+        if warn_on_unresolved_placeholders and unresolved_placeholders:
             unresolved_placeholders_message = f"Placeholders {unresolved_placeholders} have not been resolved. Pass them as keyword arguments to compile()."
             langfuse_logger.warning(unresolved_placeholders_message)
 
@@ -446,7 +458,10 @@ def get_langchain_prompt(
             List of messages in the format expected by Langchain's ChatPromptTemplate:
             (role, content) tuples for regular messages or MessagesPlaceholder objects for unresolved placeholders.
         """
-        compiled_messages = self.compile(**kwargs)
+        compiled_messages = self._compile(
+            warn_on_unresolved_placeholders=False,
+            **kwargs,
+        )
         langchain_messages: List[Union[Tuple[str, str], Any]] = []
 
         for msg in compiled_messages:

tests/unit/test_prompt_compilation.py

@@ -804,6 +804,8 @@ def test_chat_prompt_with_placeholders_langchain(self):
 
     def test_get_langchain_prompt_with_unresolved_placeholders(self):
         """Test that unresolved placeholders become MessagesPlaceholder objects."""
+        from unittest.mock import patch
+
         from langfuse.api import Prompt_Chat
         from langfuse.model import ChatPromptClient
 
@@ -826,10 +828,13 @@ def test_get_langchain_prompt_with_unresolved_placeholders(self):
         )
 
         # Call get_langchain_prompt without resolving placeholder
-        langchain_messages = prompt_client.get_langchain_prompt(
-            role="helpful",
-            task="coding",
-        )
+        with patch("langfuse.logger.langfuse_logger.warning") as mock_warning:
+            langchain_messages = prompt_client.get_langchain_prompt(
+                role="helpful",
+                task="coding",
+            )
+
+        mock_warning.assert_not_called()
 
         # Should have 3 items: system message, MessagesPlaceholder, user message
         assert len(langchain_messages) == 3