fix(persistence): restore pre-identity sessions

packages/core/agent-loop/tests/resume.spec.ts

@@ -5,7 +5,7 @@ import { mkdtemp, rm } from 'node:fs/promises'
 import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import LlmService from '@deepseek-ai/dsh-llm'
-import SessionStore, { Session, SessionId } from '@deepseek-ai/dsh-session'
+import SessionStore, { SESSION_FORMAT_VERSION, Session, SessionId } from '@deepseek-ai/dsh-session'
 import type { SessionEvent } from '@deepseek-ai/dsh-session'
 import SystemPrompt from '@deepseek-ai/dsh-system-prompt'
 import ToolRegistry from '@deepseek-ai/dsh-tools'
@@ -77,6 +77,65 @@ function throwUnknown(value: unknown): never {
 }
 
 describe('the session-persistence Agent Note: AgentLoop factory create/resume', () => {
+  it('resumes a session persisted before messages gained identities', async () => {
+    const sessionId = SessionId('pre-identity-resume')
+    const first = await persistentHarness(new MockAdapter([]))
+    await first.ctx.sessionPersistence.create({
+      version: SESSION_FORMAT_VERSION,
+      id: sessionId,
+      createdAt: 1,
+    })
+    await first.ctx.sessionPersistence.append(sessionId, [
+      { type: 'turn/start', seq: 0, time: 1, data: { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } } },
+      {
+        type: 'user/message',
+        seq: 1,
+        time: 2,
+        data: { content: [{ type: 'text', text: 'old question' }], source: { kind: 'user' } },
+        surfaceOp: 'append',
+      },
+      { type: 'step/start', seq: 2, time: 3, data: { turn: 1, step: 1 } },
+      {
+        type: 'assistant/message',
+        seq: 3,
+        time: 4,
+        data: {
+          turn: 1,
+          step: 1,
+          content: [{ type: 'text', text: 'old answer' }],
+          provenance: { provider: 'mock', model: 'mock' },
+        },
+        surfaceOp: 'append',
+      },
+      { type: 'step/end', seq: 4, time: 5, data: { turn: 1, step: 1 } },
+      { type: 'turn/end', seq: 5, time: 6, data: { turn: 1, reason: { kind: 'completed' } } },
+    ] as unknown as SessionEvent[])
+    await first.ctx.fiber.dispose()
+
+    const ctx = await mountPersistentHarness(first.root, new MockAdapter([textResponse('new answer')]))
+    const handle = await ctx.agents.resume({
+      resumeSessionId: sessionId,
+      agentOptions: { provider: 'mock', model: 'mock' },
+    })
+    expect(handle.agent.session.deriveMessages()).toMatchObject([
+      { id: `legacy-message:${sessionId}:1`, role: 'user' },
+      { id: `legacy-message:${sessionId}:3`, role: 'assistant' },
+    ])
+
+    handle.agent.followup(createUserMessage({
+      content: [{ type: 'text', text: 'new question' }],
+      source: { kind: 'user' },
+    }))
+    await waitForIdle(ctx, handle.agent)
+    expect(handle.agent.session.deriveMessages()).toHaveLength(4)
+    expect(handle.agent.session.events.at(-1)).toMatchObject({
+      type: 'turn/end',
+      data: { reason: { kind: 'completed' } },
+    })
+    await handle.dispose()
+    await ctx.fiber.dispose()
+  })
+
   it('normalizes a non-Error resume publication failure for rollback and rethrows it', async () => {
     const sessionId = SessionId('unknown-resume-failure-s')
     const root = await persistSession(sessionId)

packages/core/session/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/core/session/README.md
-README.md: 40516d12180de9c30efd40fdffa873da20ddacb3
-README.zh.md: 43842643a3434c741f219f7b6c26622cddfae8e7
+README.md: a9b6905dcf2b8ef1f75595e567273f7a3150a412
+README.zh.md: f1a5e97e32d1ad1abcd6ad96e6c621af9972e989

packages/core/session/README.md

@@ -142,5 +142,5 @@ Logging causes no invalidation, and exact reconstruction preserves request-prefi
 
 - **Session branching/tree** (pi-style entry tree) — deferred unless needed beyond boundary-based `fork()`.
 - **`fork()` cuts only at stable boundaries of live sessions** — the selected prefix must end outside an open turn and the source must be in the store; forking a persisted-but-unloaded session is excluded from the [fork API](../../../.agents/notes/implemented/feature/2026-06-30-session-store-fork-api.md).
-- **`SESSION_FORMAT_VERSION` stays pinned at `0`** — pre-release, no compatibility implied: a backend rejects any other version, and no migration path exists until the first release ([policy](../../../AGENTS.md)).
+- **`SESSION_FORMAT_VERSION` stays pinned at `0`** — pre-release, no broad compatibility implied: `Session` accepts only current seed shapes and a backend rejects any other version. Narrow storage import upgrades belong to the persistence boundary ([policy](../../../AGENTS.md), [pre-identity message recovery](../../../.agents/notes/implemented/bug-fix/2026-07-28-load-pre-identity-session-messages.md)).
 - **`TurnEndReasonMap` omits the ACP-named `refusal` / `max_turn_requests` variants** — producer-gated: they land when an adapter or the loop first emits them.

packages/core/session/README.zh.md

@@ -142,5 +142,5 @@
 
 - **会话分支／树**（pi 风格条目树）：除非需要超越基于边界的 `fork()` 能力，否则暂缓。
 - **`fork()` 仅在实时会话的稳定边界处切分**：所选前缀结束时不得有开放轮次，且源会话必须位于存储中；[fork API](../../../.agents/notes/implemented/feature/2026-06-30-session-store-fork-api.md) 不支持对已持久化但未加载的会话进行 fork。
-- **`SESSION_FORMAT_VERSION` 固定为 `0`**：预发布阶段不承诺兼容性；后端会拒绝其他任何版本，首次发布前不提供迁移路径（[政策](../../../AGENTS.md)）。
+- **`SESSION_FORMAT_VERSION` 固定为 `0`**：预发布阶段不承诺广泛兼容性；`Session` 只接受当前 seed 形状，后端会拒绝其他任何版本。范围受限的存储导入升级应由持久化边界负责（[政策](../../../AGENTS.md)、[消息标识机制引入前的消息恢复](../../../.agents/notes/implemented/bug-fix/2026-07-28-load-pre-identity-session-messages.md)）。
 - **`TurnEndReasonMap` 不含 ACP（Agent Client Protocol）命名的 `refusal`／`max_turn_requests` 变体**：受生产方约束；只有当适配器或循环首次产生这些变体时才加入。