fix: enforce message snapshot invariants

packages/session-query/session-query/src/index.ts

@@ -5,7 +5,7 @@
  */
 
 import { Context, Service } from 'cordis'
-import { Session, type SessionId } from '@deepseek-ai/dsh-session'
+import { Session, snapshotSessionEvent, type SessionId } from '@deepseek-ai/dsh-session'
 import { foldSessionTitle } from '@deepseek-ai/dsh-session-title'
 import type { SessionTitleSnapshot } from '@deepseek-ai/dsh-session-title'
 import type {
@@ -45,7 +45,6 @@ import {
   materializeSessionResultFilters,
 } from './filters.ts'
 import * as tracing from './tracing.ts'
-import { snapshotEvent } from './snapshot.ts'
 
 export type * from './types.ts'
 export { SessionSearchCursor } from './cursor.ts'
@@ -147,7 +146,7 @@ export abstract class SessionQueryService extends Service {
     new Session(sessionId, loaded.events, loaded.header)
     return {
       session: structuredClone(loaded.header),
-      events: loaded.events.map(snapshotEvent),
+      events: loaded.events.map(snapshotSessionEvent),
     }
   }
 
@@ -331,9 +330,11 @@ export abstract class SessionQueryService extends Service {
     }
     const startSeq = Math.max(0, seq - before)
     const endSeq = Math.min(loaded.events.length - 1, seq + after)
-    const targetSnapshot = snapshotEvent(target)
+    const targetSnapshot = snapshotSessionEvent(target)
     const events = loaded.events.slice(startSeq, endSeq + 1)
-      .map(event => event === target ? targetSnapshot : snapshotEvent(event))
+      .map(event => event === target
+        ? targetSnapshot
+        : snapshotSessionEvent(event))
     return {
       session: structuredClone(loaded.header),
       target: targetSnapshot,

packages/session-query/session-query/src/snapshot.ts

@@ -1,27 +0,0 @@
-/** Detached session-query snapshots that preserve message immutability. */
-
-import { deepFreeze } from '@deepseek-ai/dsh-llm'
-import type { SessionEvent } from '@deepseek-ai/dsh-session'
-
-/**
- * Clone one event while retaining the invariant that every identified message is frozen.
- * @param event - source event from one corpus observation.
- * @returns a detached event whose message value, if any, is deeply frozen.
- */
-export function snapshotEvent<T extends SessionEvent>(event: T): T {
-  const snapshot = structuredClone(event)
-  switch (snapshot.type) {
-    case 'user/message':
-      deepFreeze(snapshot.data)
-      break
-    case 'assistant/message':
-    case 'tool/result':
-    case 'steering/message':
-      deepFreeze(snapshot.data.message)
-      break
-    default:
-      // SessionEventMap is merge-extensible; plugin-owned log-only events carry no core message.
-      break
-  }
-  return snapshot
-}

packages/session-query/session-query/src/tracing.ts

@@ -1,6 +1,6 @@
 /** One-shot session-lineage and event-relationship tracing helpers. */
 
-import { foldSurface, isSurfaceEvent } from '@deepseek-ai/dsh-session'
+import { foldSurface, isSurfaceEvent, snapshotSessionEvent } from '@deepseek-ai/dsh-session'
 import type { SessionEvent, SessionId, SurfaceEvent, SurfaceEventType } from '@deepseek-ai/dsh-session'
 import { SessionQueryError } from './config.ts'
 import type {
@@ -10,7 +10,6 @@ import type {
   SessionLineageTrace,
   SessionRecord,
 } from './types.ts'
-import { snapshotEvent } from './snapshot.ts'
 
 interface EventLogAnalysis {
   records: SessionEventRecord[]
@@ -52,7 +51,7 @@ export function currentSurfaceEvents(
         'SESSION_QUERY_INVALID_SURFACE',
       )
     }
-    return snapshotEvent(event)
+    return snapshotSessionEvent(event)
   })
 }