refactor(openai-shim): extract request executor helpers

src/services/api/credentialPool.test.ts

@@ -45,6 +45,34 @@ test('CredentialPool cools down recoverable failures', () => {
   expect(pool.next()?.value).toBe('key-a')
 })
 
+test('CredentialPool does not let an older success clear a newer cooldown', () => {
+  const pool = new CredentialPool(['key-a', 'key-b'])
+  const firstA = pool.next()
+  const keyB = pool.next()
+
+  pool.reportFailure(keyB, 'auth', 0)
+  const concurrentA = pool.next()
+  pool.reportFailure(concurrentA, 'cooldown', 30_000)
+  pool.reportSuccess(firstA)
+
+  expect(pool.hasAvailableCredential()).toBe(false)
+})
+
+test('CredentialPool lets a stale auth failure permanently disable a cooled key', () => {
+  let now = 1_000
+  const pool = new CredentialPool(['key-a', 'key-b'], () => now)
+  const firstA = pool.next()
+  const keyB = pool.next()
+
+  pool.reportFailure(keyB, 'auth', 0)
+  const concurrentA = pool.next()
+  pool.reportFailure(concurrentA, 'cooldown', 30_000)
+  pool.reportFailure(firstA, 'auth', 0)
+
+  now += 30_001
+  expect(pool.hasAvailableCredential()).toBe(false)
+})
+
 test('CredentialPool falls back to least-recently failed credential when all are cooling down', () => {
   let now = 1_000
   const pool = new CredentialPool(['key-a', 'key-b'], () => now)
@@ -56,5 +84,5 @@ test('CredentialPool falls back to least-recently failed credential when all are
   const second = pool.next()
   pool.reportFailure(second, 'cooldown', 30_000)
 
-  expect(pool.next()).toEqual({ value: 'key-a', index: 0 })
+  expect(pool.next()).toEqual({ value: 'key-a', index: 0, generation: 1 })
 })

src/services/api/credentialPool.ts

@@ -3,13 +3,15 @@ export type CredentialPoolFailureKind = 'auth' | 'cooldown'
 export type CredentialLease = {
   value: string
   index: number
+  generation: number
 }
 
 type CredentialState = {
   value: string
   disabled: boolean
   cooldownUntil: number
   lastFailureAt: number
+  generation: number
 }
 
 export class CredentialPool {
@@ -23,6 +25,7 @@ export class CredentialPool {
       disabled: false,
       cooldownUntil: 0,
       lastFailureAt: 0,
+      generation: 0,
     }))
     this.now = now
   }
@@ -44,7 +47,7 @@ export class CredentialPool {
         continue
       }
       this.cursor = (index + 1) % this.credentials.length
-      return { value: candidate.value, index }
+      return { value: candidate.value, index, generation: candidate.generation }
     }
 
     let leastRecentlyFailedIndex = -1
@@ -66,13 +69,30 @@ export class CredentialPool {
 
     const fallback = this.credentials[leastRecentlyFailedIndex]
     this.cursor = (leastRecentlyFailedIndex + 1) % this.credentials.length
-    return { value: fallback.value, index: leastRecentlyFailedIndex }
+    return {
+      value: fallback.value,
+      index: leastRecentlyFailedIndex,
+      generation: fallback.generation,
+    }
+  }
+
+  hasAvailableCredential(): boolean {
+    const now = this.now()
+    return this.credentials.some(
+      credential => !credential.disabled && credential.cooldownUntil <= now,
+    )
   }
 
   reportSuccess(lease: CredentialLease | null): void {
     if (!lease) return
     const credential = this.credentials[lease.index]
-    if (!credential || credential.value !== lease.value) return
+    if (
+      !credential ||
+      credential.value !== lease.value ||
+      credential.generation !== lease.generation
+    ) {
+      return
+    }
     credential.cooldownUntil = 0
   }
 
@@ -83,9 +103,16 @@ export class CredentialPool {
   ): void {
     if (!lease) return
     const credential = this.credentials[lease.index]
-    if (!credential || credential.value !== lease.value) return
+    if (!credential || credential.value !== lease.value) {
+      return
+    }
+    // Auth failures must evict a key even when a newer cooldown advanced its lease.
+    if (kind !== 'auth' && credential.generation !== lease.generation) {
+      return
+    }
 
     const now = this.now()
+    credential.generation += 1
     credential.lastFailureAt = now
     if (kind === 'auth') {
       credential.disabled = true