fix: Rollback compaction handling from _get_contents

The sorting may cause problems in complex cases so rolling it back. Will implement it with a non-sorting approach.

PiperOrigin-RevId: 816420710

Author: hangfei

src/google/adk/flows/llm_flows/contents.py

@@ -236,40 +236,17 @@ def _contains_empty_content(event: Event) -> bool:
 def _get_contents(
     current_branch: Optional[str], events: list[Event], agent_name: str = ''
 ) -> list[types.Content]:
-  """Retrieves and processes events into a list of Contents for the LLM request.
-
-  This function prepares the conversation history for the LLM by applying
-  several transformations:
-  1.  **Initial Filtering**: Removes events that are empty, do not belong
-      to the current invocation branch, or are related to authentication
-      or request confirmation.
-  2.  **Compaction Handling**: Identifies the latest compaction event. If found,
-      it replaces all events covered by the compaction range with the compacted
-      summary content. Only events *after* the compaction's end timestamp
-      are included in addition to the summary. If no compaction event exists,
-      all filtered events are considered.
-  3.  **Transcription Aggregation**: Combines consecutive
-      `input_transcription` and `output_transcription` events into single
-      'user' and 'model' role `types.Content` events, respectively.
-  4.  **Multi-Agent Presentation**: Reformats messages from other agents
-      (i.e., not the current `agent_name` and not 'user') to be presented
-      as user-role context, prefixed with `[agent_name] said:`. Compactor
-      events are included directly without reformatting.
-  5.  **Function Call/Response Rearrangement**: Ensures proper pairing of
-      asynchronous function calls and responses within the event history.
-  6.  **Content Conversion**: Converts the final list of processed events
-      into `types.Content` objects, removing any client-side function call IDs.
+  """Get the contents for the LLM request.
+
+  Applies filtering, rearrangement, and content processing to events.
 
   Args:
-    current_branch: The current invocation branch ID. Events outside this branch
-      will be filtered out.
-    events: A list of session events to process.
-    agent_name: The name of the agent currently running. Used to distinguish
-      between events from the current agent, other agents, and the user.
+    current_branch: The current branch of the agent.
+    events: Events to process.
+    agent_name: The name of the agent.
 
   Returns:
-    A list of `types.Content` objects representing the conversation history
-    to be sent to the LLM.
+    A list of processed contents.
   """
   accumulated_input_transcription = ''
   accumulated_output_transcription = ''
@@ -292,55 +269,18 @@ def _get_contents(
 
     raw_filtered_events.append(event)
 
-  # Find the latest compaction event.
-  latest_compaction_event = None
-  for event in reversed(raw_filtered_events):
-    if event.actions and event.actions.compaction:
-      latest_compaction_event = event
-      break
-
-  events_to_process = []
-  if latest_compaction_event:
-    compaction = latest_compaction_event.actions.compaction
-    if (
-        compaction.start_timestamp is not None
-        and compaction.end_timestamp is not None
-    ):
-      # Add the compacted event itself.
-      new_event = Event(
-          timestamp=compaction.end_timestamp,
-          author='compactor',
-          content=compaction.compacted_content,
-          branch=latest_compaction_event.branch,
-          invocation_id=latest_compaction_event.invocation_id,
-          actions=latest_compaction_event.actions,
-      )
-      events_to_process.append(new_event)
-
-      # Add events from raw_filtered_events that are *after* the
-      # latest compaction's end timestamp.
-      for event in raw_filtered_events:
-        if event.timestamp > compaction.end_timestamp:
-          events_to_process.append(event)
-  else:
-    # No compaction events, process all raw filtered events.
-    events_to_process = raw_filtered_events
-
-  # Sort by timestamp to ensure chronological order.
-  events_to_process.sort(key=lambda x: x.timestamp)
-
   filtered_events = []
   # aggregate transcription events
-  for i in range(len(events_to_process)):
-    event = events_to_process[i]
+  for i in range(len(raw_filtered_events)):
+    event = raw_filtered_events[i]
     if not event.content:
       # Convert transcription into normal event
       if event.input_transcription and event.input_transcription.text:
         accumulated_input_transcription += event.input_transcription.text
         if (
-            i != len(events_to_process) - 1
-            and events_to_process[i + 1].input_transcription
-            and events_to_process[i + 1].input_transcription.text
+            i != len(raw_filtered_events) - 1
+            and raw_filtered_events[i + 1].input_transcription
+            and raw_filtered_events[i + 1].input_transcription.text
         ):
           continue
         event = event.model_copy(deep=True)
@@ -353,9 +293,9 @@ def _get_contents(
       elif event.output_transcription and event.output_transcription.text:
         accumulated_output_transcription += event.output_transcription.text
         if (
-            i != len(events_to_process) - 1
-            and events_to_process[i + 1].output_transcription
-            and events_to_process[i + 1].output_transcription.text
+            i != len(raw_filtered_events) - 1
+            and raw_filtered_events[i + 1].output_transcription
+            and raw_filtered_events[i + 1].output_transcription.text
         ):
           continue
         event = event.model_copy(deep=True)
@@ -384,9 +324,8 @@ def _get_contents(
   contents = []
   for event in result_events:
     content = copy.deepcopy(event.content)
-    if content:
-      remove_client_function_call_id(content)
-      contents.append(content)
+    remove_client_function_call_id(content)
+    contents.append(content)
   return contents