Stop retried and deleted actions from corrupting story context and memories

Three fallout bugs from keeping the retried action row alive (906ba42),
plus two long-standing cursor bugs the same investigation turned up.

Retry context leak: the row being regenerated is still attached to the
adventure, so it was replayed as established story and the model wrote a
continuation of the attempt it was meant to replace — the story visibly
blended both takes. It leaked into four places, not one: history replay,
story-card trigger matching, in-scene NPC detection, and the memory-bank
similarity query. Adds a shared context.story_actions(exclude_action_id),
threaded through build_context and retrieve_memories.

Memory holdback: a memory could summarize the just-generated turn; retry
rewrites Action.text but memory_cursor has already advanced, so the memory
was never regenerated and went on describing narration no longer in the
story. settled_story_actions() holds the newest action back one turn —
only the last action is retryable, so that makes it unreachable. The
settled list is always a prefix, so cursors stay valid and nothing is
skipped. The run_post_turn clamp deliberately still uses the full count:
clamping to settled rewinds legacy adventures a step and double-covers an
action.

Cursor bookkeeping: memory_cursor is a position into story_actions() while
Memory.source_* are Action.index values, and the two diverge as soon as
anything is deleted. Deleting a middle action slid a never-summarized
action into the covered range, skipping it forever; and pruning a memory
left the actions it covered stranded behind the cursor. Adds
note_action_removed() (called before the delete in delete_action and
undo_turn) and a rewind in prune_dangling_memories. delete_action also
now prunes at all, which it never did.

Not addressed: editing an already-summarized action still leaves its
memory stale, and the cumulative story summary can't have one fact
un-mixed from it.

117 backend tests pass, including new test_memory_settling.py (12) and
two retry-context regression tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UeQVy5bEjLhfgWNc27Efet

backend/tests/test_memory_settling.py

@@ -0,0 +1,283 @@
+"""Memories must never describe an attempt the player can still retry away.
+
+Only the last action is retryable, so summarization holds the newest action
+back one turn (memorybank.settled_story_actions). Without that, a memory could
+cover the just-generated AI turn; retrying it rewrites Action.text but the
+memory cursor has already advanced, so the memory is never regenerated and goes
+on describing narration that is no longer in the story.
+
+    python -m pytest tests/test_memory_settling.py -v
+"""
+import asyncio
+import os
+import tempfile
+
+_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
+_tmp.close()
+os.environ["AIDND_DB_PATH"] = _tmp.name
+os.environ.pop("AIDND_DATABASE_URL", None)
+os.environ.pop("DATABASE_URL", None)
+
+import pytest
+
+from app import memorybank, models
+from app.database import Base, SessionLocal, engine
+
+
+class StubSummarizer:
+    """Records every excerpt handed to the summarizer."""
+
+    def __init__(self):
+        self.excerpts: list[str] = []
+
+    async def complete(self, system, user, **kwargs):
+        self.excerpts.append(user)
+        return f"Memory {len(self.excerpts)}."
+
+
+@pytest.fixture()
+def db():
+    Base.metadata.create_all(bind=engine)
+    session = SessionLocal()
+    try:
+        yield session
+    finally:
+        session.close()
+        Base.metadata.drop_all(bind=engine)
+
+
+def make_adventure(db, action_count: int) -> models.Adventure:
+    """An adventure whose actions alternate player/AI, newest last."""
+    user = models.User(is_guest=False, email="memory@example.com")
+    db.add(user)
+    db.flush()
+    settings = models.Settings(user_id=user.id, api_key="enc:dummy", model="test-model")
+    db.add(settings)
+    adventure = models.Adventure(
+        user_id=user.id, title="Cave", script_state={}, auto_summarize=True
+    )
+    db.add(adventure)
+    db.flush()
+    for i in range(action_count):
+        db.add(models.Action(
+            adventure_id=adventure.id, index=i,
+            type="ai" if i % 2 else "do", text=f"Action {i}.",
+        ))
+    db.commit()
+    db.refresh(adventure)
+    return adventure
+
+
+def run_memories(db, adventure, stub, monkeypatch):
+    monkeypatch.setattr(memorybank, "summary_provider", lambda s: stub)
+    settings = db.query(models.Settings).first()
+    asyncio.run(memorybank._create_due_memories(adventure, settings, db))
+
+
+# ------------------------------------------------------------------- settling
+
+def test_settled_actions_holds_back_the_newest(db):
+    adventure = make_adventure(db, 5)
+    settled = memorybank.settled_story_actions(adventure)
+    assert [a.index for a in settled] == [0, 1, 2, 3]
+
+
+def test_settled_actions_is_a_prefix_so_cursors_stay_valid(db):
+    """The safety property behind the whole approach: dropping the newest
+    action can never renumber or skip an earlier one."""
+    adventure = make_adventure(db, 9)
+    full = memorybank.story_actions(adventure)
+    settled = memorybank.settled_story_actions(adventure)
+    assert full[: len(settled)] == settled
+
+
+def test_settled_actions_on_a_one_action_story(db):
+    adventure = make_adventure(db, 1)
+    assert memorybank.settled_story_actions(adventure) == []
+
+
+# ------------------------------------------------------- the bug this prevents
+
+def test_memory_never_covers_the_newest_retryable_action(db, monkeypatch):
+    """cursor=6 with 12 actions is exactly the case that used to bite: the
+    6-action block ends on the newest action, which is still retryable."""
+    adventure = make_adventure(db, 12)
+    adventure.memory_cursor = 6
+    db.commit()
+
+    stub = StubSummarizer()
+    run_memories(db, adventure, stub, monkeypatch)
+
+    assert stub.excerpts == []  # only 11 settled — one short of a block
+    assert db.query(models.Memory).count() == 0
+    assert adventure.memory_cursor == 6
+
+
+def test_the_block_lands_a_turn_later_without_the_newest_action(db, monkeypatch):
+    """One more action and the same block is summarized — minus the new one."""
+    adventure = make_adventure(db, 13)
+    adventure.memory_cursor = 6
+    db.commit()
+
+    stub = StubSummarizer()
+    run_memories(db, adventure, stub, monkeypatch)
+
+    assert len(stub.excerpts) == 1
+    excerpt = stub.excerpts[0]
+    assert "Action 11." in excerpt  # the block's real last action
+    assert "Action 12." not in excerpt  # the newest, still retryable
+    memory = db.query(models.Memory).one()
+    assert (memory.source_start, memory.source_end) == (6, 11)
+    assert adventure.memory_cursor == 12
+
+
+def test_first_memory_waits_one_action_past_memory_start(db, monkeypatch):
+    adventure = make_adventure(db, memorybank.MEMORY_START)
+    stub = StubSummarizer()
+    run_memories(db, adventure, stub, monkeypatch)
+    assert stub.excerpts == []
+
+    db.add(models.Action(
+        adventure_id=adventure.id, index=memorybank.MEMORY_START, type="do", text="Later.",
+    ))
+    db.commit()
+    db.refresh(adventure)
+    run_memories(db, adventure, stub, monkeypatch)
+    # 12 settled actions = two full blocks, caught up in one run (MAX_MEMORIES_
+    # PER_RUN allows 5); neither may reach the newly added newest action.
+    assert len(stub.excerpts) == 2
+    assert not any("Later." in e for e in stub.excerpts)
+
+
+def test_legacy_caught_up_adventure_is_not_rewound(db, monkeypatch):
+    """An adventure summarized under the OLD rule can have memory_cursor equal
+    to its action count. The run_post_turn clamp must use the FULL count, not
+    the settled one — clamping to settled would rewind the cursor a step and
+    re-cover an already-summarized action in the next block."""
+    adventure = make_adventure(db, 12)
+    db.add(models.Memory(adventure_id=adventure.id, text="A", source_start=0, source_end=5))
+    db.add(models.Memory(adventure_id=adventure.id, text="B", source_start=6, source_end=11))
+    adventure.memory_cursor = 12
+    adventure.summary_cursor = 12
+    db.commit()
+
+    # The clamp as run_post_turn applies it.
+    count = len(memorybank.story_actions(adventure))
+    adventure.memory_cursor = min(adventure.memory_cursor, count)
+    assert adventure.memory_cursor == 12  # not rewound to 11
+
+    # Grow the story and let the next block form.
+    for i in range(12, 25):
+        db.add(models.Action(adventure_id=adventure.id, index=i, type="do", text=f"Action {i}."))
+    db.commit()
+    db.refresh(adventure)
+    run_memories(db, adventure, StubSummarizer(), monkeypatch)
+
+    covered: dict[int, int] = {}
+    for m in db.query(models.Memory).all():
+        for i in range(m.source_start, m.source_end + 1):
+            covered[i] = covered.get(i, 0) + 1
+    assert [i for i, c in covered.items() if c > 1] == []  # no action summarized twice
+    assert [i for i in range(max(covered) + 1) if i not in covered] == []  # no gaps
+
+
+def test_no_memories_before_memory_start(db, monkeypatch):
+    adventure = make_adventure(db, 8)
+    stub = StubSummarizer()
+    run_memories(db, adventure, stub, monkeypatch)
+    assert stub.excerpts == []
+
+
+# ------------------------------------------- deleting already-summarized ground
+
+def orphans(db, adventure) -> list[int]:
+    """Action indices the cursor calls summarized that no memory describes."""
+    covered: set[int] = set()
+    for m in db.query(models.Memory).filter_by(adventure_id=adventure.id):
+        covered |= set(range(m.source_start, m.source_end + 1))
+    actions = memorybank.story_actions(adventure)
+    return [a.index for a in actions[: adventure.memory_cursor] if a.index not in covered]
+
+
+def summarized_adventure(db):
+    """13 actions with two memories covering indices 0-11, cursor at 12."""
+    adventure = make_adventure(db, 13)
+    db.add(models.Memory(adventure_id=adventure.id, text="A", source_start=0, source_end=5))
+    db.add(models.Memory(adventure_id=adventure.id, text="B", source_start=6, source_end=11))
+    adventure.memory_cursor = 12
+    adventure.summary_cursor = 12
+    db.commit()
+    db.refresh(adventure)
+    return adventure
+
+
+def test_deleting_a_middle_action_does_not_skip_a_later_one(db):
+    """memory_cursor counts positions, so removing an earlier action slides a
+    never-summarized one into the covered range unless the cursor slides too."""
+    adventure = summarized_adventure(db)
+    victim = db.query(models.Action).filter_by(adventure_id=adventure.id, index=5).one()
+
+    memorybank.note_action_removed(adventure, victim)
+    db.delete(victim)
+    db.commit()
+    db.refresh(adventure)
+
+    assert adventure.memory_cursor == 11  # slid down by one
+    assert orphans(db, adventure) == []
+
+
+def test_deleting_a_later_action_leaves_cursors_alone(db):
+    """Only actions *before* the cursor shift it."""
+    adventure = summarized_adventure(db)
+    victim = db.query(models.Action).filter_by(adventure_id=adventure.id, index=12).one()
+
+    memorybank.note_action_removed(adventure, victim)
+    db.delete(victim)
+    db.commit()
+    db.refresh(adventure)
+
+    assert adventure.memory_cursor == 12
+    assert orphans(db, adventure) == []
+
+
+def test_pruning_a_memory_rewinds_to_where_it_started(db):
+    """Discarding a memory isn't enough — the actions it covered are still
+    behind the cursor, so they must be handed back to the summarizer."""
+    adventure = summarized_adventure(db)
+    # Delete back past index 11, so memory B (6..11) covers a missing action.
+    for index in (12, 11):
+        victim = db.query(models.Action).filter_by(adventure_id=adventure.id, index=index).one()
+        memorybank.note_action_removed(adventure, victim)
+        db.delete(victim)
+    db.flush()
+    db.expire(adventure, ["actions"])
+
+    assert memorybank.prune_dangling_memories(adventure, db) == 1
+    db.commit()
+    db.refresh(adventure)
+
+    assert [m.text for m in db.query(models.Memory).all()] == ["A"]
+    assert adventure.memory_cursor == 6  # back to where the discarded memory began
+    assert orphans(db, adventure) == []
+
+
+def test_repeated_deletes_never_orphan_an_action(db):
+    """The scenario that motivated this: undo/delete-last, over and over."""
+    adventure = summarized_adventure(db)
+    for _ in range(6):
+        actions = memorybank.story_actions(adventure)
+        if not actions:
+            break
+        victim = max(actions, key=lambda a: a.index)
+        memorybank.note_action_removed(adventure, victim)
+        db.delete(victim)
+        db.flush()
+        db.expire(adventure, ["actions"])
+        memorybank.prune_dangling_memories(adventure, db)
+        count = len(memorybank.story_actions(adventure))
+        adventure.memory_cursor = min(adventure.memory_cursor, count)
+        adventure.summary_cursor = min(adventure.summary_cursor, count)
+        db.commit()
+        db.refresh(adventure)
+        assert orphans(db, adventure) == []
+        assert adventure.memory_cursor <= len(memorybank.story_actions(adventure))

backend/tests/test_retry_variants.py

@@ -39,6 +39,7 @@ class ScriptedProvider:
     """Streams the next canned reply each call, so successive retries differ."""
     replies: list = []
     calls = 0
+    prompts: list = []  # every assembled (system, story) pair, for context assertions
 
     def __init__(self, *a, **k):
         pass
@@ -46,6 +47,7 @@ class ScriptedProvider:
     async def generate(self, parts: PromptParts, *, temperature, max_tokens):
         index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
         ScriptedProvider.calls += 1
+        ScriptedProvider.prompts.append((parts.system, parts.story))
         reply = ScriptedProvider.replies[index]
         if isinstance(reply, Exception):
             raise reply
@@ -79,6 +81,7 @@ def client(monkeypatch):
 
     ScriptedProvider.replies = ["Attempt one."]
     ScriptedProvider.calls = 0
+    ScriptedProvider.prompts = []
     monkeypatch.setattr(adventures, "OpenAICompatibleProvider", ScriptedProvider)
     monkeypatch.setattr(auth, "resolve_provider_config", lambda s: auth.ProviderConfig(
         "http://fake", "k", "test-model", False))
@@ -146,6 +149,35 @@ def test_retry_keeps_the_discarded_attempt(client):
     assert [v["active"] for v in r.json()] == [False, True]
 
 
+def test_retry_context_excludes_the_attempt_being_replaced(client):
+    """The whole point of a retry is a fresh take on the *same* turn. The row
+    now survives the retry (it holds the variant history), so it is still in
+    `adventure.actions` while the replacement context is assembled — it must be
+    filtered out, or the model is asked to continue *past* the attempt it is
+    supposed to be replacing and writes a sequel that blends both."""
+    ScriptedProvider.replies = ["Attempt one.", "Attempt two."]
+    _play(client)
+    _retry(client)
+
+    retry_story = ScriptedProvider.prompts[-1][1]
+    assert "Attempt one." not in retry_story
+    # The turn's own player action must still be there — it's what to respond to.
+    assert "look around" in retry_story
+    assert "You enter a cave." in retry_story
+
+
+def test_retry_context_keeps_earlier_ai_turns(client):
+    """Only the action being retried is dropped, not AI history in general."""
+    ScriptedProvider.replies = ["First turn.", "Second turn.", "Second, again."]
+    _play(client, "go north")
+    _play(client, "go south")
+    _retry(client)
+
+    retry_story = ScriptedProvider.prompts[-1][1]
+    assert "First turn." in retry_story
+    assert "Second turn." not in retry_story
+
+
 def test_never_retried_action_has_no_variants(client):
     _play(client)
     last = _actions(client)[-1]