feat(session-query): checkpoint build round 1

packages/core/session/tests/session.spec.ts

@@ -350,6 +350,43 @@ describe('SessionStore', () => {
     expect(observed).toBe(0)
   })
 
+  it('announces a cloned header only after the session leaves the store', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SessionStore)
+    const observations: Array<{ id: string; live: boolean }> = []
+    ctx.on('session/removed', (header) => {
+      observations.push({ id: header.id, live: ctx.sessions.get(header.id) !== undefined })
+      header.createdAt = -1
+    })
+    const session = ctx.sessions.prepare(SessionId('removed'), { meta: { createdAt: 7 } })
+    const detach = ctx.sessions.enter(session)
+
+    detach()
+    await Promise.resolve()
+    await Promise.resolve()
+
+    expect(observations).toEqual([{ id: 'removed', live: false }])
+    expect(session.header.createdAt).toBe(7)
+    // A repeated disposer cannot remove or announce a later same-id owner.
+    const replacement = ctx.sessions.create(SessionId('removed'))
+    detach()
+    expect(ctx.sessions.get(replacement.id)).toBe(replacement)
+    expect(observations).toHaveLength(1)
+  })
+
+  it('contains rejected session/removed listeners during teardown', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SessionStore)
+    ctx.on('session/removed', () => Promise.reject(new Error('observer failed')))
+    const session = ctx.sessions.prepare(SessionId('contained'))
+    const detach = ctx.sessions.enter(session)
+
+    expect(detach).not.toThrow()
+    await Promise.resolve()
+    await Promise.resolve()
+    expect(ctx.sessions.get(session.id)).toBeUndefined()
+  })
+
   it('rolls back the session (and onAppend) when a session/created listener throws (P1-1)', async () => {
     const ctx = new Context()
     await ctx.plugin(SessionStore)

packages/core/session/tests/surface.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import type { SessionEvent, SurfaceEvent, SurfaceEventType } from '@deepseek-ai/dsh-session'
-import { Session, SessionId, isSurfaceEligibleType, isSurfaceEvent } from '@deepseek-ai/dsh-session'
+import { Session, SessionId, foldSurface, isSurfaceEligibleType, isSurfaceEvent } from '@deepseek-ai/dsh-session'
 import { CallId } from '@deepseek-ai/dsh-llm'
 
 /** Build a minimal session with turn boundaries and a single user message. */
@@ -14,6 +14,34 @@ function surfaceSession(): Session {
 }
 
 describe('SurfaceManager', () => {
+  it('shares exact nodes and nested replacement ranges with foldSurface', () => {
+    const s = new Session(SessionId('shared-fold'))
+    s.append('user/message', { content: [{ type: 'text', text: 'a' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
+    s.append('user/message', { content: [{ type: 'text', text: 'b' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
+    s.append('assistant/message', { turn: 1, step: 1, content: [{ type: 'text', text: 'summary' }] }, { surfaceOp: { op: 'replace', start: 0, end: 0 }, sourceEventSeqs: [0] })
+    s.append('assistant/message', { turn: 1, step: 2, content: [{ type: 'text', text: 'summary 2' }] }, { surfaceOp: { op: 'replace', start: 2, end: 1 }, sourceEventSeqs: [2, 1] })
+
+    const folded = foldSurface(s.events)
+    expect(folded.nodes).toEqual(s.surface.nodes)
+    expect(folded.replacements).toEqual([
+      { seq: 2, start: 0, end: 0, shadowedSeqs: [0] },
+      { seq: 3, start: 2, end: 1, shadowedSeqs: [2, 1] },
+    ])
+    folded.nodes[0]!.next = 99
+    folded.replacements[0]!.shadowedSeqs.push(99)
+    expect(s.surface.nodes).toEqual([{ seq: 3, prev: null, next: null }])
+    expect(foldSurface(s.events).replacements[0]!.shadowedSeqs).toEqual([0])
+  })
+
+  it('foldSurface reports the same invalid replacement failures as the incremental manager', () => {
+    const s = new Session(SessionId('shared-fold-invalid'))
+    s.append('user/message', { content: [{ type: 'text', text: 'a' }], source: { kind: 'user' } }, { surfaceOp: 'append' })
+    s.append('assistant/message', { turn: 1, step: 1, content: [] }, { surfaceOp: { op: 'replace', start: 42, end: 0 }, sourceEventSeqs: [0] })
+
+    expect(() => foldSurface(s.events)).toThrow(/start seq 42 not found/)
+    expect(() => s.surface.nodes).toThrow(/start seq 42 not found/)
+  })
+
   it('rebuilds a linked list from surfaceOp: append markers', () => {
     const s = surfaceSession()
     const nodes = s.surface.nodes