Merge branch 'main' into fix/vertex-anyof-schema-sanitization

Author: rohityan

src/google/adk/apps/compaction.py

@@ -20,6 +20,7 @@
 from google.genai import types
 
 from ..agents.base_agent import BaseAgent
+from ..events._rewind_events import _apply_rewinds
 from ..events.event import Event
 from ..sessions.base_session_service import BaseSessionService
 from ..sessions.session import Session
@@ -386,16 +387,22 @@ async def _run_compaction_for_token_threshold_config(
   if config.token_threshold is None or config.event_retention_size is None:
     return False
 
+  # Drop rewound invocations so the summary covers only live events, consistent
+  # with prompt building and sliding-window compaction (all route through
+  # _apply_rewinds); otherwise rewound content would leak back into future
+  # prompts via the compaction summary.
+  events = _apply_rewinds(session.events)
+
   prompt_token_count = _latest_prompt_token_count(
-      session.events,
+      events,
       current_branch=current_branch,
       agent_name=agent_name,
   )
   if prompt_token_count is None or prompt_token_count < config.token_threshold:
     return False
 
   events_to_compact = _events_to_compact_for_token_threshold(
-      events=session.events,
+      events=events,
       event_retention_size=config.event_retention_size,
   )
   if not events_to_compact:
@@ -530,7 +537,11 @@ async def _run_compaction_for_sliding_window(
     runner loop) is responsible for appending it to the session, so that
     persistence of this event stays at the runtime's synchronization point.
   """
-  events = session.events
+  # Drop rewound invocations first so the summary covers only live events. This
+  # keeps the compactor consistent with prompt building (the contents processor
+  # also applies rewinds); otherwise rewound content would leak back into future
+  # prompts via the compaction summary.
+  events = _apply_rewinds(session.events)
   if not events:
     return
 

src/google/adk/events/_rewind_events.py

@@ -0,0 +1,55 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Helpers for resolving which events are live after rewinds."""
+
+from __future__ import annotations
+
+from .event import Event
+
+
+def _apply_rewinds(events: list[Event]) -> list[Event]:
+  """Returns ``events`` with rewound invocations removed.
+
+  Iterates backward. When an event carries
+  ``actions.rewind_before_invocation_id == X``, drops that event together with
+  every event between it and the earliest event of invocation ``X`` (inclusive),
+  then resumes the backward walk from there.
+
+  This is the single source of truth for "which events are live" after rewinds.
+  Both LLM prompt building (``google.adk.flows.llm_flows.contents``) and context
+  compaction (``google.adk.apps.compaction``) must agree on it, otherwise
+  rewound content can leak back into prompts through a compaction summary.
+
+  Args:
+    events: The full event history, in chronological order.
+
+  Returns:
+    The chronological subset of ``events`` that survives all rewinds.
+  """
+  kept: list[Event] = []
+  i = len(events) - 1
+  while i >= 0:
+    event = events[i]
+    if event.actions and event.actions.rewind_before_invocation_id:
+      rewind_invocation_id = event.actions.rewind_before_invocation_id
+      for j in range(0, i, 1):
+        if events[j].invocation_id == rewind_invocation_id:
+          i = j
+          break
+    else:
+      kept.append(event)
+    i -= 1
+  kept.reverse()
+  return kept

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

@@ -24,6 +24,7 @@
 
 from ...agents.invocation_context import InvocationContext
 from ...events._branch_path import _BranchPath
+from ...events._rewind_events import _apply_rewinds
 from ...events.event import Event
 from ...models.llm_request import LlmRequest
 from ._base_llm_processor import BaseLlmRequestProcessor
@@ -709,24 +710,10 @@ def _get_contents(
   accumulated_input_transcription = ''
   accumulated_output_transcription = ''
 
-  # Filter out events that are annulled by a rewind.
-  # By iterating backward, when a rewind event is found, we skip all events
-  # from that point back to the `rewind_before_invocation_id`, thus removing
-  # them from the history used for the LLM request.
-  rewind_filtered_events = []
-  i = len(events) - 1
-  while i >= 0:
-    event = events[i]
-    if event.actions and event.actions.rewind_before_invocation_id:
-      rewind_invocation_id = event.actions.rewind_before_invocation_id
-      for j in range(0, i, 1):
-        if events[j].invocation_id == rewind_invocation_id:
-          i = j
-          break
-    else:
-      rewind_filtered_events.append(event)
-    i -= 1
-  rewind_filtered_events.reverse()
+  # Filter out events that are annulled by a rewind, so the rewound history is
+  # never sent to the LLM. This is the same rewind logic the context compactor
+  # applies, keeping the two consistent (see google.adk.events._rewind_events).
+  rewind_filtered_events = _apply_rewinds(events)
 
   # Parse the events, leaving the contents and the function calls and
   # responses from the current agent.