fix(review-3.6): invalidate history caches by epoch and coalesce syncs

1 files changed, 19 insertions, 0 deletions

diff --git a/src/features/conversation-cache/cache.test.ts b/src/features/conversation-cache/cache.test.ts
index ce1c60c..4306d51 100644
--- a/src/features/conversation-cache/cache.test.ts
+++ b/src/features/conversation-cache/cache.test.ts
@@ -15,8 +15,16 @@ const chunk = (seq: number, role: "user" | "assistant" = "user"): StoredChunk =>
  */
 function createFakeStore(): ConversationChunkStore {
   const store = new Map<string, StoredChunk[]>();
+  const epochs = new Map<string, number>();
 
   return {
+    async historyEpoch(id) {
+      return epochs.get(id);
+    },
+    async reset(id, epoch) {
+      store.delete(id);
+      epochs.set(id, epoch);
+    },
     async load(conversationId) {
       return store.get(conversationId) ?? [];
     },
@@ -33,6 +41,7 @@ function createFakeStore(): ConversationChunkStore {
 
     async delete(conversationId) {
       store.delete(conversationId);
+      epochs.delete(conversationId);
     },
 
     async index() {
@@ -195,3 +204,13 @@ describe("cache.delete", () => {
     expect(result).toEqual([]);
   });
 });
+
+it("serializes invalidation and rejects stale epoch commits", async () => {
+  const store = createFakeStore();
+  const cache = createConversationCache(store);
+  await store.append("c", [chunk(1)]); // Legacy rows have no trusted epoch.
+  expect(await cache.commit("c", [chunk(101)], 1)).toEqual([chunk(101)]);
+  await Promise.all([cache.commit("c", [chunk(102)], 1), cache.reset("c", 2)]);
+  expect(await cache.commit("c", [chunk(103)], 1)).toEqual([]);
+  expect(await store.historyEpoch("c")).toBe(2);
+});