test,chore: clear the static and coverage lanes for the cache stack

Static: the cache package.json files array matches the workspace
constraint shape, the unused dsh-storage-json devDependency is dropped
(tests run on the memory backend), and docs/module-graph.md is
regenerated for the new package edge.

Coverage: two unreachable branches deleted rather than tested —
coldSnapshot's floor-0 tail reuse (a baseSeq-0 restore never throws and
an unrelated record still carries a usable watermark) and flushSoft's
non-mandatory clean-skip (throttle triggers only fire dirty). New tests
close the real gaps: write() on a never-dirty session and the non-JSON
unit-state rejection, plugin disposal clearing armed interval timers,
cachedSnapshot's all-version-mismatched and cwd-identity arms, the
zero-units empty-log cut, the coordinator seek-hook ladder (suffix /
not-found / plain failure / abort-reason relay), and the superseded-
retirement race proving forget()'s exact-entry guard.

docs/module-graph.md

@@ -211,6 +211,7 @@ flowchart TD
   end
   subgraph group_session_projection["packages/session-projection"]
     pkg_session_projection["session-projection"]
+    pkg_session_projection_cache["session-projection-cache"]
   end
   subgraph group_storage["packages/storage"]
     pkg_storage["storage"]
@@ -502,6 +503,11 @@ flowchart TD
   pkg_pty --> pkg_invariants
   pkg_scripts --> pkg_app_boot
   pkg_scripts --> pkg_invariants
+  pkg_session_projection_cache --> pkg_invariants
+  pkg_session_projection_cache --> pkg_session
+  pkg_session_projection_cache --> pkg_session_persistence
+  pkg_session_projection_cache --> pkg_session_projection
+  pkg_session_projection_cache --> pkg_storage_domain
   pkg_tasks --> pkg_agent
   pkg_tasks --> pkg_brand
   pkg_tasks --> pkg_invariants
@@ -1003,6 +1009,7 @@ flowchart TD
 | [`time-context`](../packages/context/time-context) | `context` | [`agent`](../packages/core/agent), [`invariants`](../packages/support/invariants), [`session`](../packages/core/session) |
 | [`pty`](../packages/pty/pty) | `pty` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`invariants`](../packages/support/invariants) |
 | [`scripts`](../packages/sdk/scripts) | `sdk` | [`app-boot`](../packages/ui/app-boot), [`invariants`](../packages/support/invariants) |
+| [`session-projection-cache`](../packages/session-projection/session-projection-cache) | `session-projection` | [`invariants`](../packages/support/invariants), [`session`](../packages/core/session), [`session-persistence`](../packages/session-persistence/session-persistence), [`session-projection`](../packages/session-projection/session-projection), [`storage-domain`](../packages/storage/storage-domain) |
 | [`tasks`](../packages/tasks/tasks) | `tasks` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`invariants`](../packages/support/invariants), [`session`](../packages/core/session) |
 | [`session-telemetry`](../packages/telemetry/session-telemetry) | `telemetry` | [`agent`](../packages/core/agent), [`invariants`](../packages/support/invariants), [`session`](../packages/core/session) |
 | [`workflow`](../packages/workflow/workflow) | `workflow` | [`agent`](../packages/core/agent), [`brand`](../packages/util/brand), [`invariants`](../packages/support/invariants), [`llm`](../packages/llm/llm), [`session`](../packages/core/session) |

packages/session-persistence/session-persistence/tests/persistence.spec.ts

@@ -161,6 +161,13 @@ class ControlledBackend implements PersistenceBackend<never> {
   repairAttempts = 0
   beforeAppend?: (attempt: number) => Promise<void>
   beforeLoadStored?: (attempt: number, signal?: AbortSignal) => Promise<void>
+  /** When set, the declared seek hook delegates here so readFrom exercises it; unset throws (tests set it first). */
+  seekHook?: (id: SessionId, fromSeq: number, signal?: AbortSignal) => Promise<StoredPrefix<never> | undefined>
+
+  loadStoredFrom(id: SessionId, fromSeq: number, signal?: AbortSignal): Promise<StoredPrefix<never> | undefined> {
+    if (this.seekHook === undefined) throw new Error('seekHook not configured for this test')
+    return this.seekHook(id, fromSeq, signal)
+  }
 
   async loadStored(id: SessionId, signal?: AbortSignal): Promise<StoredPrefix<never> | undefined> {
     await this.beforeLoadStored?.(++this.loadAttempts, signal)
@@ -457,6 +464,58 @@ describe('PersistenceCoordinator observation cancellation', () => {
     }
   })
 
+  it('readFrom via the seek hook: serves the suffix, maps undefined to not-found, and relays hook failures by abort state', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SessionStore)
+    const backend = new ControlledBackend()
+    const id = SessionId('seek-read-from')
+    const log = oneTurnLog()
+    backend.store.set(id, { meta: meta(id), events: log })
+    let coordinator!: PersistenceCoordinator<never>
+    const fiber = await ctx.plugin(Object.assign((inner: Context) => {
+      coordinator = new PersistenceCoordinator(inner, backend)
+    }, { inject: ['sessions'] }))
+
+    try {
+      // Happy path through the hook: only the suffix comes back, detached.
+      backend.seekHook = async (hookId, fromSeq) => {
+        const entry = backend.store.get(hookId)
+        if (entry === undefined) return undefined
+        return { meta: structuredClone(entry.meta), events: entry.events.filter(e => e.seq >= fromSeq) }
+      }
+      const suffix = await coordinator.readFrom(id, 3)
+      expect(suffix.events).toEqual(log.slice(3))
+      // The hook's undefined is the seam's not-found.
+      await expect(coordinator.readFrom(SessionId('missing-seek'), 0)).rejects.toThrow('not found')
+
+      // A hook failure with no cancellation in play propagates as-is.
+      const hookFailure = new Error('seek backend exploded')
+      backend.seekHook = () => Promise.reject(hookFailure)
+      await expect(coordinator.readFrom(id, 0)).rejects.toBe(hookFailure)
+
+      // A hook failure after cancellation surfaces the caller's abort reason,
+      // not the backend's internal teardown error. The abort fires only once
+      // the hook is provably entered, so the failure exercises the catch (not
+      // the pre-invocation throwIfAborted).
+      const controller = new AbortController()
+      const reason = new Error('read-from cancelled mid-hook')
+      let hookEntered = false
+      backend.seekHook = async (_hookId, _fromSeq, signal) => {
+        hookEntered = true
+        await new Promise<void>((resolve) => { signal?.addEventListener('abort', () => { resolve() }, { once: true }) })
+        throw new Error('backend teardown after abort')
+      }
+      const pending = coordinator.readFrom(id, 0, controller.signal)
+      const observed = pending.catch((error: unknown) => error)
+      await vi.waitFor(() => { expect(hookEntered).toBe(true) })
+      controller.abort(reason)
+      expect(await observed).toBe(reason)
+    } finally {
+      await fiber.dispose()
+      await ctx.fiber.dispose()
+    }
+  })
+
   it('rejects a cancelled inspect while an in-flight retirement drain is still pending', async () => {
     const ctx = new Context()
     await ctx.plugin(SessionStore)
@@ -541,6 +600,66 @@ describe('PersistenceCoordinator retirement', () => {
     }
   })
 
+  it('a superseded retirement leaves the successor lifecycle\'s pending drain in place', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SessionStore)
+    const backend = new ControlledBackend()
+    let coordinator!: PersistenceCoordinator<never>
+    const backendFiber = await ctx.plugin(Object.assign((inner: Context) => {
+      coordinator = new PersistenceCoordinator(inner, backend)
+    }, { inject: ['sessions'] }))
+    const internals = coordinator as unknown as CoordinatorInternals
+    const readGate = Promise.withResolvers<boolean>()
+
+    try {
+      const id = SessionId('superseded-retirement')
+      // First lifecycle: unmaterialized (zero events), so a same-id successor
+      // may legally reclaim the abandoned id later.
+      let first!: Session
+      const firstFiber = await ctx.plugin(Object.assign((inner: Context) => {
+        first = inner.sessions.create(id)
+      }, { inject: ['sessions'] }))
+      await ctx.sessions.flush(first)
+
+      // Occupy the per-id serialize chain with a gated read: everything the
+      // two retirements queue stays pending behind it. (Attempt counting
+      // starts here — an absent beforeLoadStored short-circuits the optional
+      // call without evaluating its ++ argument.)
+      backend.beforeLoadStored = async (attempt) => {
+        if (attempt === 1) await readGate.promise
+      }
+      const parked = coordinator.inspect(id).catch((error: unknown) => error)
+      await vi.waitFor(() => { expect(backend.loadAttempts).toBe(1) })
+
+      // First retirement queues behind the gate and stays pending.
+      await firstFiber.dispose()
+      await vi.waitFor(() => { expect(internals.retirements.has(id)).toBe(true) })
+      const firstRetirement = internals.retirements.get(id)
+
+      // Successor lifecycle retires while the first drain is still in flight:
+      // retire() replaces the map entry synchronously.
+      const secondFiber = await ctx.plugin(Object.assign((inner: Context) => {
+        inner.sessions.create(id)
+      }, { inject: ['sessions'] }))
+      await secondFiber.dispose()
+      await vi.waitFor(() => {
+        expect(internals.retirements.get(id)).not.toBe(firstRetirement)
+      })
+
+      // Release the chain: the first drain settles and its forget() must not
+      // delete the successor's entry (exact-entry guard); the successor's own
+      // forget() then clears the map.
+      readGate.resolve(true)
+      expect(await parked).toBeInstanceOf(Error) // the parked inspect (not found) is observed
+      await firstRetirement
+      await vi.waitFor(() => { expect(internals.retirements.has(id)).toBe(false) })
+    } finally {
+      readGate.resolve(true)
+      await backendFiber.dispose()
+      await ctx.fiber.dispose()
+    }
+  })
+
   it('a replacement queued before retirement cleanup still collides with the live owner', async () => {
     const ctx = new Context()
     await ctx.plugin(SessionStore)

packages/session-projection/session-projection-cache/package.json

@@ -21,7 +21,6 @@
   "files": [
     "lib/index.js",
     "lib/invariant.js",
-    "lib/types/**/*.js",
     "lib/types/**/*.d.ts",
     "lib/types/**/*.d.ts.map",
     "src"
@@ -46,7 +45,6 @@
     "@deepseek-ai/dsh-session-projection": "workspace:^",
     "@deepseek-ai/dsh-storage": "workspace:^",
     "@deepseek-ai/dsh-storage-domain": "workspace:^",
-    "@deepseek-ai/dsh-storage-json": "workspace:^",
     "cordis": "^4.0.0-rc.7"
   }
 }

packages/session-projection/session-projection-cache/src/index.ts

@@ -186,9 +186,10 @@ export class SessionProjectionCache extends Service {
       restored = this.ctx.sessionProjections.restore(cached, tail.events, floor)
     } catch {
       // The recoverable restore failures: an unrelated record, or a row
-      // overreaching the stored log end (or predating the floor). All
-      // resolve identically — discard the cache and refold the full log.
-      const whole = floor === 0 && related ? tail : await persistence.readFrom(id, 0, signal)
+      // overreaching the stored log end (or predating the floor). Both imply
+      // floor > 0 (baseSeq-0 restores never throw and an unrelated record
+      // still carried a usable watermark), so the full log is a fresh read.
+      const whole = await persistence.readFrom(id, 0, signal)
       restored = this.ctx.sessionProjections.restore({}, whole.events, 0)
     }
     await this.putSoft(id, identityOf(tail.meta), restored.checkpoint, 'cold-read write-back')
@@ -237,11 +238,12 @@ export class SessionProjectionCache extends Service {
     }, 'sessionProjectionCache.timers')
   }
 
-  /** One fail-soft durable checkpoint: skip when clean, log on failure. */
+  /**
+   * One fail-soft durable checkpoint. Every caller has work by construction:
+   * the throttle triggers only fire dirty (markClean clears the timer with
+   * the counter) and the two mandatory points write unconditionally.
+   */
   private async flushSoft(session: Session, trigger: string): Promise<void> {
-    const state = this.dirty.get(session)
-    const mandatory = trigger === 'turn/end' || trigger === 'detach'
-    if (!mandatory && (state === undefined || state.pending === 0)) return
     try {
       await this.write(session)
     } catch (error) {

packages/session-projection/session-projection-cache/tests/cache.spec.ts

@@ -58,7 +58,8 @@ function fakePersistence(logs: Map<string, SessionEvent[]>) {
 }
 
 /** Header shape for cachedSnapshot calls (fake logs stamp createdAt 0, no cwd). */
-const headerOf = (id: SessionId, createdAt = 0) => ({ version: 0, id, createdAt })
+const headerOf = (id: SessionId, createdAt = 0, cwd?: string) =>
+  ({ version: 0, id, createdAt, ...cwd === undefined ? {} : { cwd } })
 
 interface HarnessOptions {
   pool?: MemoryMediaPool
@@ -166,6 +167,39 @@ describe('SessionProjectionCache write policy', () => {
     expect(storedRows(pool, session.id)?.['cache-test/marks']?.state).toEqual({ marks: ['slow'] })
   })
 
+  it('write() on a never-dirty session checkpoints directly and rejects a non-JSON unit state', async () => {
+    const { ctx, pool } = await harness()
+    // Never dirtied: no events — write() still lands the init-derived cut.
+    const clean = ctx.sessions.create(SessionId('clean-write'))
+    await ctx.sessionProjectionCache.write(clean)
+    expect(storedRows(pool, clean.id)?.['cache-test/marks']).toEqual({ stateVersion: 1, observedSeq: -1, state: null })
+    // A unit whose state violates the plain-JSON contract fails the write loud.
+    ctx.sessionProjections.register({
+      key: 'cache-test/marks2' as never,
+      schema: { parse: (value: unknown) => value } as never,
+      init: () => new Map<string, string>(),
+      apply: (state: unknown) => state,
+      view: () => null as never,
+      stateVersion: 1,
+    } as never)
+    await expect(ctx.sessionProjectionCache.write(clean)).rejects.toThrow('not losslessly JSON-serializable')
+  })
+
+  it('plugin disposal clears armed interval timers and leaves cleaned sessions alone', async () => {
+    vi.useFakeTimers()
+    const { ctx, pool, fiber } = await harness({ config: { writeEveryEvents: 100, writeIntervalMs: 5000 } })
+    const armed = ctx.sessions.create(SessionId('armed'))
+    const cleaned = ctx.sessions.create(SessionId('cleaned'))
+    mark(armed, ['pending']) // timer armed, no write yet
+    mark(cleaned, ['done'])
+    endTurn(cleaned) // mandatory write; markClean leaves {pending: 0, timer: undefined} in the map
+    await vi.runAllTicks()
+    await fiber.dispose()
+    // The armed timer died with the plugin: advancing time writes nothing.
+    await vi.advanceTimersByTimeAsync(10_000)
+    expect(storedRows(pool, armed.id)).toBeUndefined()
+  })
+
   it('contains a durable write failure: logs a warning, event path unharmed, next write self-heals', async () => {
     const { ctx, pool } = await harness()
     const warn = vi.spyOn(ctx.logger, 'warn').mockImplementation(() => {})
@@ -281,6 +315,41 @@ describe('SessionProjectionCache cold read', () => {
     expect(storedRecord(samePool, SessionId('reborn'))?.identity).toEqual({ createdAt: 0 })
   })
 
+  it('cachedSnapshot returns undefined when every stored row is version-mismatched', async () => {
+    const pool = new MemoryMediaPool()
+    seedRow(pool, 'all-stale', { stateVersion: 99, observedSeq: 4, state: { marks: ['old'] } })
+    const { cache } = await harness({ pool })
+    expect(cache.cachedSnapshot(headerOf(SessionId('all-stale')))).toBeUndefined()
+  })
+
+  it('binds identity on cwd too: a matching cwd serves, a moved session does not', async () => {
+    const pool = new MemoryMediaPool()
+    seedRow(pool, 'homed', { stateVersion: 1, observedSeq: 2, state: { marks: ['w'] } }, { createdAt: 0, cwd: '/work' })
+    const { cache } = await harness({ pool })
+    const id = SessionId('homed')
+    expect(cache.cachedSnapshot(headerOf(id, 0, '/work'))?.values['cache-test/marks']).toEqual({ marks: ['w'] })
+    expect(cache.cachedSnapshot(headerOf(id, 0, '/elsewhere'))).toBeUndefined()
+    expect(cache.cachedSnapshot(headerOf(id, 0))).toBeUndefined()
+  })
+
+  it('dates an empty stored log at -1 in the zero-units topology', async () => {
+    const pool = new MemoryMediaPool()
+    const logs = new Map([['empty', [] as SessionEvent[]]])
+    const ctx = new Context()
+    contexts.push(ctx)
+    await ctx.plugin(Storage)
+    ctx.storage.backend.register('memory', new MemoryStorageBackend(pool))
+    const facility = new DomainFacility(ctx, { backend: 'memory', routes: {} })
+    ctx.storage.mount('domain', facility)
+    ctx.provide('storageDomain', facility)
+    await ctx.plugin(SessionStore)
+    await ctx.plugin(SessionProjectionRegistry)
+    ctx.provide('sessionPersistence', fakePersistence(logs) as never)
+    await ctx.plugin(SessionProjectionCache, { writeEveryEvents: 100, writeIntervalMs: 60_000 })
+    await expect(ctx.sessionProjectionCache.coldSnapshot(SessionId('empty')))
+      .resolves.toEqual({ asOfSeq: -1, values: {} })
+  })
+
   it('cachedSnapshot serves identity-matching rows with the cut watermark and refuses unrelated ones', async () => {
     const pool = new MemoryMediaPool()
     seedRow(pool, 'listed', { stateVersion: 1, observedSeq: 4, state: { marks: ['t'] } })

pnpm-lock.yaml

@@ -3493,9 +3493,6 @@ importers:
       '@deepseek-ai/dsh-storage-domain':
         specifier: workspace:^
         version: link:../../storage/storage-domain
-      '@deepseek-ai/dsh-storage-json':
-        specifier: workspace:^
-        version: link:../../storage/storage-json
       cordis:
         specifier: ^4.0.0-rc.7
         version: 4.0.0-rc.7(@cordisjs/plugin-include@1.0.4)(@cordisjs/plugin-loader@1.0.0-rc.5)