fix: protect live session sync caches

packages/ui/src/sync/__tests__/eviction.test.ts

@@ -1,10 +1,11 @@
 import { describe, expect, test } from "bun:test"
-import type { PermissionRequest, QuestionRequest } from "@opencode-ai/sdk/v2/client"
+import type { Message, PermissionRequest, QuestionRequest } from "@opencode-ai/sdk/v2/client"
 import {
   canDisposeDirectory,
   hasPendingBlockingRequests,
   pickDirectoriesToEvict,
 } from "../eviction"
+import { getProtectedSessionCacheIds, pickSessionCacheEvictions } from "../session-cache"
 import { INITIAL_STATE, type DirState, type State } from "../types"
 
 const DAY_MS = 24 * 60 * 60 * 1000
@@ -133,3 +134,42 @@ describe("canDisposeDirectory", () => {
     expect(canDisposeDirectory(baseInput)).toBe(true)
   })
 })
+
+describe("session cache eviction", () => {
+  test("protects live and blocking sessions from per-directory cache eviction", () => {
+    const protectedIds = getProtectedSessionCacheIds({
+      session_status: {
+        ses_busy: { type: "busy" },
+        ses_idle: { type: "idle" },
+      },
+      session_diff: {},
+      todo: {},
+      message: {
+        ses_streaming: [{ id: "msg_1", role: "assistant", time: { created: 1 } } as Message],
+      },
+      part: {},
+      permission: {
+        ses_permission: [buildPermission({ sessionID: "ses_permission" })],
+      },
+      question: {
+        ses_question: [buildQuestion({ sessionID: "ses_question" })],
+      },
+    })
+
+    expect(protectedIds).toEqual(new Set(["ses_busy", "ses_streaming", "ses_permission", "ses_question"]))
+
+    const seen = new Set(["ses_old", "ses_busy", "ses_permission", "ses_question", "ses_streaming", "ses_current"])
+    const evicted = pickSessionCacheEvictions({
+      seen,
+      keep: "ses_current",
+      preserve: protectedIds,
+      limit: 2,
+    })
+
+    expect(evicted).toEqual(["ses_old"])
+    expect(seen.has("ses_busy")).toBe(true)
+    expect(seen.has("ses_permission")).toBe(true)
+    expect(seen.has("ses_question")).toBe(true)
+    expect(seen.has("ses_streaming")).toBe(true)
+  })
+})

packages/ui/src/sync/session-cache.ts

@@ -18,6 +18,40 @@ type SessionCache = {
   question: Record<string, QuestionRequest[] | undefined>
 }
 
+export function getProtectedSessionCacheIds(store: SessionCache): Set<string> {
+  const protectedIds = new Set<string>()
+
+  for (const [sessionID, status] of Object.entries(store.session_status ?? {})) {
+    if (status && status.type !== "idle") {
+      protectedIds.add(sessionID)
+    }
+  }
+
+  for (const [sessionID, permissions] of Object.entries(store.permission ?? {})) {
+    if ((permissions?.length ?? 0) > 0) {
+      protectedIds.add(sessionID)
+    }
+  }
+
+  for (const [sessionID, questions] of Object.entries(store.question ?? {})) {
+    if ((questions?.length ?? 0) > 0) {
+      protectedIds.add(sessionID)
+    }
+  }
+
+  for (const [sessionID, messages] of Object.entries(store.message ?? {})) {
+    const lastMessage = messages?.[messages.length - 1]
+    if (
+      lastMessage?.role === "assistant"
+      && typeof (lastMessage as { time?: { completed?: number } }).time?.completed !== "number"
+    ) {
+      protectedIds.add(sessionID)
+    }
+  }
+
+  return protectedIds
+}
+
 export function dropSessionCaches(store: SessionCache, sessionIDs: Iterable<string>) {
   const stale = new Set(Array.from(sessionIDs).filter(Boolean))
   if (stale.size === 0) return

packages/ui/src/sync/sync-context.tsx

@@ -223,6 +223,11 @@ async function repairSessionParts(
   if (records.length === 0) return
 
   store.setState((state: DirectoryStore) => {
+    const nextMessages = records
+      .map((record: { info: Message }) => stripMessageDiffSnapshots(record.info))
+      .sort((a, b) => cmp(a.id, b.id))
+    const currentMessages = state.message[sessionID] ?? []
+    const mergedMessages = mergeMessages(currentMessages, nextMessages)
     const nextPartState = { ...state.part }
     for (const record of records) {
       const messageId = record?.info?.id
@@ -237,7 +242,10 @@ async function repairSessionParts(
         nextPartState[messageId] = newParts
       }
     }
-    return { part: nextPartState }
+    return {
+      message: mergedMessages !== currentMessages ? { ...state.message, [sessionID]: mergedMessages } : state.message,
+      part: nextPartState,
+    }
   })
 }
 

packages/ui/src/sync/types.ts

@@ -113,7 +113,7 @@ export const MAX_DIR_STORES = 30
 export const DIR_IDLE_TTL_MS = 20 * 60 * 1000
 export const SESSION_RECENT_WINDOW = 4 * 60 * 60 * 1000
 export const SESSION_RECENT_LIMIT = 50
-export const SESSION_CACHE_LIMIT = 8
+export const SESSION_CACHE_LIMIT = 40
 
 export const INITIAL_STATE: State = {
   project: "",

packages/ui/src/sync/use-sync.ts

@@ -10,7 +10,7 @@ import {
   type OptimisticItem,
 } from "./optimistic"
 import { useDirectoryStore, useSyncSDK, useSyncDirectory, useChildStoreManager } from "./sync-context"
-import { dropSessionCaches } from "./session-cache"
+import { dropSessionCaches, getProtectedSessionCacheIds } from "./session-cache"
 import { stripMessageDiffSnapshots } from "./sanitize"
 import {
   shouldSkipSessionPrefetch,
@@ -135,14 +135,16 @@ export function useSync() {
   const touch = useCallback(
     (sessionID: string) => {
       const s = seenFor()
+      const protectedIds = getProtectedSessionCacheIds(store.getState())
       const stale = pickSessionCacheEvictions({
         seen: s,
         keep: sessionID,
         limit: SESSION_CACHE_LIMIT,
+        preserve: protectedIds,
       })
       evict(directory, stale)
     },
-    [directory, seenFor, evict],
+    [directory, seenFor, evict, store],
   )
 
   // Optimistic operations