feat: do not merge messages with same role (#846)

---------

Signed-off-by: Louis Mandel <[email protected]>

Author: mandel

src/pdl/pdl_utils.py

@@ -1,6 +1,6 @@
 import fnmatch
 import json
-from typing import Any, Generator, Generic, Mapping, Sequence, TypeVar
+from typing import Any, Generator, Generic, Sequence, TypeVar
 
 from .pdl_ast import (
     ContributeTarget,
@@ -106,42 +106,22 @@ def get_contribute_value(
     return None
 
 
-def messages_concat(
+def _messages_concat(
     messages1: list[dict[str, Any]], messages2: list[dict[str, Any]]
 ) -> list[dict[str, Any]]:
-    if len(messages1) == 0:
-        return messages2
-    if len(messages2) == 0:
-        return messages1
-    left = messages1[-1]
-    right = messages2[0]
-    if (
-        left["role"] == right["role"] and simple_message(left) and simple_message(right)
-    ):  # test that there are no other keys
-        return (
-            messages1[:-1]
-            + [{"role": left["role"], "content": left["content"] + right["content"]}]
-            + messages2[1:]
-        )
     return messages1 + messages2
 
 
 def lazy_messages_concat(
     messages1: LazyMessages, messages2: LazyMessages
 ) -> LazyMessages:
-    return lazy_apply2(messages_concat, messages1, messages2)
+    return lazy_apply2(_messages_concat, messages1, messages2)
 
 
 def messages_to_str(messages: LazyMessages) -> str:
     return "\n".join([str(msg) for msg in messages.result()])
 
 
-def simple_message(message: Mapping[str, Any]) -> bool:
-    if message.keys() == {"role", "content"} and message["content"] is not None:
-        return True
-    return False
-
-
 def remove_none_values_from_message(message: dict) -> dict[str, Any]:
     ret = {}
     for key, value in message.items():