Python: Keep interleaved messages in order when keeping a call/result group

Per review: the keep path still appended later results right after the
call and removed them from the working slice, so a history such as
[call, user, result] came back as [call, result, user]. Append only the
current message and let each result be appended when its own index is
reached. The skip path still drops the whole group.

Extends test_extract_range_preserve_pairs_parallel_calls_filtered_result
with a message interleaved between a parallel call and its results.

Signed-off-by: Pujitha Paladugu <10557236+pujitha24@users.noreply.github.com>

Author: pujitha24

python/semantic_kernel/contents/history_reducer/chat_history_reducer_utils.py

@@ -245,15 +245,9 @@ def extract_range(
                             # remove it from the slice so we don't process it again
                             sliced.remove(paired_idx)
                     continue
-                # keep all
+                # keep all: each paired message is appended when its own index is reached,
+                # so messages interleaved between a call and its results keep their order
                 extracted.append(msg)
-                for paired_idx in paired_indices:
-                    if paired_idx > idx and paired_idx in sliced:
-                        # We'll skip the pair in the normal iteration by removing from slice
-                        # but add it to extracted right now
-                        extracted.append(history[paired_idx])
-                        sliced.remove(paired_idx)
-                    # if paired_idx < idx, it was already processed, so do not add duplicates
                 i += 1
                 continue
             # If the paired_idx is outside [start, end), there's no conflict

python/tests/unit/contents/test_chat_history_reducer_utils.py

@@ -274,3 +274,9 @@ def test_extract_range_preserve_pairs_parallel_calls_filtered_result():
         history, start=2, end=len(history), filter_func=lambda m: m is result_paris, preserve_pairs=True
     )
     assert extracted == [result_tokyo, done]
+
+    # A message interleaved between the call and its results keeps its position
+    note = ChatMessageContent(role=AuthorRole.USER, content="also Tokyo")
+    history = [call, note, result_paris, result_tokyo]
+    extracted = extract_range(history, start=0, end=len(history), preserve_pairs=True)
+    assert extracted == history