fix(invariants): enforce runtime relationships

packages/llm/llm-retry/src/invariant.ts

@@ -0,0 +1,97 @@
+/** Package-owned durable retry-event invariants. @module @deepseek-ai/dsh-llm-retry/invariant */
+
+import type { Context } from 'cordis'
+import type { Session, SessionEvent } from '@deepseek-ai/dsh-session'
+import { MAX_TIMER_DELAY_MS } from '@deepseek-ai/dsh-timeout'
+import type { InvariantFailure, InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+import type {} from './index.ts'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-llm-retry'
+
+/** Cordis companion plugin name. */
+export const name = 'llm-retry-invariant'
+/** Service required before the companion can reserve package ownership. */
+export const inject = ['invariants']
+
+/** Validate one retry record against the open turn and most recently closed step. */
+function validateRetry(
+  history: readonly SessionEvent[],
+  event: SessionEvent<'llm/retry'>,
+  fail: InvariantFailure,
+): void {
+  const { turn, step, retry, maxRetries, delayMs } = event.data
+  if (!Number.isSafeInteger(retry) || retry < 1) {
+    fail('llm/retry retry must be a positive safe integer')
+  }
+  if (!Number.isSafeInteger(maxRetries) || maxRetries < 1 || retry > maxRetries) {
+    fail(`llm/retry retry ${retry} must not exceed a positive safe maxRetries ${maxRetries}`)
+  }
+  if (!(delayMs > 0 && delayMs <= MAX_TIMER_DELAY_MS)) {
+    fail(`llm/retry delayMs must be within 1..${MAX_TIMER_DELAY_MS}`)
+  }
+
+  const currentTurnEvents: SessionEvent[] = []
+  let openTurn: number | undefined
+  for (const prior of history.slice().reverse()) {
+    if (prior.type === 'turn/end') fail('llm/retry must be appended inside an open turn')
+    if (prior.type === 'turn/start') {
+      openTurn = prior.data.turn
+      break
+    }
+    currentTurnEvents.push(prior)
+  }
+  if (openTurn === undefined) fail('llm/retry must be appended inside an open turn')
+  if (turn !== openTurn) {
+    fail(`llm/retry names turn ${turn}, but the open turn is ${openTurn}`)
+  }
+
+  let closedStep: number | undefined
+  for (const prior of currentTurnEvents) {
+    if (prior.type === 'step/start') {
+      fail(`llm/retry must follow step/end, but step ${prior.data.step} is still open`)
+    }
+    if (prior.type === 'step/end') {
+      closedStep = prior.data.step
+      break
+    }
+  }
+  if (closedStep === undefined || step !== closedStep) {
+    fail(`llm/retry names step ${step}, but the latest closed step is ${String(closedStep)}`)
+  }
+
+  const priorRetries = currentTurnEvents
+    .filter((prior): prior is SessionEvent<'llm/retry'> => prior.type === 'llm/retry')
+  if (priorRetries.some(prior => prior.data.step === step)) {
+    fail(`llm/retry duplicates the retry record for turn ${turn}/step ${step}`)
+  }
+  const priorRetry = priorRetries[0]
+  if (priorRetry !== undefined && retry <= priorRetry.data.retry) {
+    fail(`llm/retry retry ${retry} must increase after retry ${priorRetry.data.retry}`)
+  }
+}
+
+/** Validate every retry record already present in one loaded session. */
+function validateSession(session: Session, fail: InvariantFailure): void {
+  for (const [index, event] of session.events.entries()) {
+    if (event.type === 'llm/retry') validateRetry(session.events.slice(0, index), event, fail)
+  }
+}
+
+/** Install validation for loaded and newly appended retry records. */
+const install: InvariantInstaller = Object.assign((ctx: Context, fail: InvariantFailure) => {
+  for (const session of ctx.sessions.list()) validateSession(session, fail)
+  ctx.on('session/created', (session) => { validateSession(session, fail) }, { global: true })
+  ctx.on('internal/dispatch', (_mode, eventName, args) => {
+    if (eventName !== 'session/event') return
+    const [session, event] = args as [Session, SessionEvent]
+    if (event.type === 'llm/retry') validateRetry(session.events, event, fail)
+  }, { global: true })
+}, { inject: ['sessions'] })
+
+/**
+ * Register the LLM retry invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))