From ac06f7fd09f178f37a342c1c09ec0cb95076a753 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=BB=84=E8=80=80=E9=91=AB=28Huang=20Yaoxin=29?=
 <174019195+YaoxinHuang@users.noreply.github.com>
Date: Sun, 20 Sep 2026 23:12:32 +0800
Subject: [PATCH 1/2] Preserve aliased messages when replacing chat history

---
 python/semantic_kernel/contents/chat_history.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/python/semantic_kernel/contents/chat_history.py b/python/semantic_kernel/contents/chat_history.py
index a773c232c7bc..58600ba4e911 100644
--- a/python/semantic_kernel/contents/chat_history.py
+++ b/python/semantic_kernel/contents/chat_history.py
@@ -300,12 +300,13 @@ def extend(self, messages: Iterable[ChatMessageContent]) -> None:
     def replace(self, messages: Iterable[ChatMessageContent]) -> None:
         """Replace the chat history with a list of messages.
 
-        This calls clear() and then extend(messages=messages).
+        The iterable is consumed before clearing the history so it can refer to the current messages.
 
         Args:
             messages: The messages to add to the history.
                 Can be a list of ChatMessageContent instances or a ChatHistory itself.
         """
+        messages = list(messages)
         self.clear()
         self.extend(messages=messages)
 

From 570ffe2199c31f608a9e20ae449bc7bb32dabca7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=BB=84=E8=80=80=E9=91=AB=28Huang=20Yaoxin=29?=
 <174019195+YaoxinHuang@users.noreply.github.com>
Date: Sun, 20 Sep 2026 23:14:28 +0800
Subject: [PATCH 2/2] Test chat history replacement from aliased iterables

---
 .../tests/unit/contents/test_chat_history.py  | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/python/tests/unit/contents/test_chat_history.py b/python/tests/unit/contents/test_chat_history.py
index 3c1b92945296..ef05a45f1282 100644
--- a/python/tests/unit/contents/test_chat_history.py
+++ b/python/tests/unit/contents/test_chat_history.py
@@ -232,6 +232,34 @@ def test_iter(chat_history: ChatHistory):
         assert message.content == messages[i]
 
 
+@pytest.mark.parametrize(
+    "get_messages",
+    [lambda history: history, lambda history: history.messages, lambda history: iter(history)],
+    ids=["history", "messages", "iterator"],
+)
+def test_replace_from_same_history(chat_history: ChatHistory, get_messages):
+    chat_history.add_user_message("Question")
+    chat_history.add_assistant_message("Answer")
+    expected_messages = list(chat_history)
+    messages = chat_history.messages
+
+    chat_history.replace(get_messages(chat_history))
+
+    assert chat_history.messages == expected_messages
+    assert chat_history.messages is messages
+
+
+def test_replace_from_filtered_history(chat_history: ChatHistory):
+    chat_history.add_system_message("Instructions")
+    chat_history.add_user_message("Question")
+    chat_history.add_assistant_message("Answer")
+    expected_messages = chat_history.messages[:2]
+
+    chat_history.replace(message for message in chat_history if message.role != AuthorRole.ASSISTANT)
+
+    assert chat_history.messages == expected_messages
+
+
 def test_eq():
     # Create two instances of ChatHistory
     chat_history1 = ChatHistory()