fix(invariants): assert runtime relationships, not API shapes

packages/compact/compact/tests/compact.spec.ts

@@ -38,7 +38,7 @@ class StubCompactService extends CompactService {
     const summaryEvent = session.append('compact/summary', {
       summary,
       shadowedRange: { start, end },
-      shadowedSeqs: [],
+      shadowedSeqs: [start],
       shadowedTokenCount: 0,
       provider: 'mock',
       model: 'stub',
@@ -50,7 +50,7 @@ class StubCompactService extends CompactService {
       endSeq: endEvent.seq,
       summary,
       shadowedRange: { start, end },
-      shadowedSeqs: [],
+      shadowedSeqs: [start],
       shadowedTokenCount: 0,
     }
   }

packages/compact/compact/tests/invariant.spec.ts

@@ -0,0 +1,90 @@
+import { describe, expect, it } from 'vitest'
+import { Context } from 'cordis'
+import SessionStore from '@deepseek-ai/dsh-session'
+import * as CompactInvariant from '@deepseek-ai/dsh-compact/invariant'
+import InvariantService from '@deepseek-ai/dsh-invariants'
+
+async function setup(): Promise<Context> {
+  const ctx = new Context()
+  await ctx.plugin(SessionStore)
+  await ctx.plugin(InvariantService)
+  await ctx.plugin(CompactInvariant)
+  return ctx
+}
+
+const summary = (overrides: Record<string, unknown> = {}) => ({
+  summary: [{ type: 'text' as const, text: 'short' }],
+  shadowedRange: { start: 2, end: 4 },
+  shadowedSeqs: [2, 3, 4],
+  shadowedTokenCount: 12,
+  provider: 'mock',
+  model: 'mock',
+  ...overrides,
+})
+
+describe('compaction invariants', () => {
+  it('accepts successful and failed compaction lifecycles', async () => {
+    const ctx = await setup()
+    const success = ctx.sessions.create()
+    success.append('compact/start', { turn: 1 })
+    success.append('compact/summary', summary())
+    success.append('compact/end', { turn: 1 })
+
+    const failed = ctx.sessions.create()
+    failed.append('compact/start', { turn: 2 })
+    failed.append('compact/end', { turn: 2, error: 'provider failed' })
+  })
+
+  it('rebuilds an open trace when the companion loads after the session', async () => {
+    const ctx = new Context()
+    await ctx.plugin(SessionStore)
+    const session = ctx.sessions.create()
+    session.append('turn/start', { turn: 1, trigger: { kind: 'message', source: { kind: 'user' } } })
+    session.append('compact/start', { turn: 3 })
+    await ctx.plugin(InvariantService)
+    await ctx.plugin(CompactInvariant)
+    expect(() => session.append('compact/end', { turn: 3, error: 'resume failed' })).not.toThrow()
+    session.append('turn/end', { turn: 1, reason: { kind: 'completed' } })
+  })
+
+  it.each([
+    ['summary without start', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/summary', summary())
+    }, /no matching compact\/start/],
+    ['nested start', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/start', { turn: 1 })
+      session.append('compact/start', { turn: 2 })
+    }, /still compacting/],
+    ['repeated summary', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/start', { turn: 1 })
+      session.append('compact/summary', summary())
+      session.append('compact/summary', summary())
+    }, /repeated within one compaction/],
+    ['empty shadow set', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/start', { turn: 1 })
+      session.append('compact/summary', summary({ shadowedSeqs: [] }))
+    }, /shadowedSeqs must be non-empty/],
+    ['wrong endpoints', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/start', { turn: 1 })
+      session.append('compact/summary', summary({ shadowedRange: { start: 1, end: 4 } }))
+    }, /shadowedRange must match/],
+    ['invalid token count', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/start', { turn: 1 })
+      session.append('compact/summary', summary({ shadowedTokenCount: -1 }))
+    }, /non-negative safe integer/],
+    ['end without start', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/end', { turn: 1, error: 'failed' })
+    }, /no matching compact\/start/],
+    ['wrong end turn', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/start', { turn: 1 })
+      session.append('compact/end', { turn: 2, error: 'failed' })
+    }, /does not match/],
+    ['success without summary', (session: ReturnType<Context['sessions']['create']>) => {
+      session.append('compact/start', { turn: 1 })
+      session.append('compact/end', { turn: 1 })
+    }, /requires one compact\/summary/],
+  ])('rejects %s', async (_name, action, message) => {
+    const ctx = await setup()
+    expect(() => { action(ctx.sessions.create()) }).toThrow(message)
+  })
+})