fix(auth): handle NaN clockDrift to fix token auto-refresh #14689
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…y#14618) Add test cases for the getTokens() method in TokenOrchestrator to verify token refresh behavior when tokens expire. These tests prove that: - Expired access tokens trigger automatic refresh - Expired ID tokens trigger automatic refresh - forceRefresh option works correctly with valid tokens - signInDetails are preserved after token refresh - NotAuthorizedException returns null and clears tokens - Network errors are thrown (not swallowed) - clientMetadata is passed to the token refresher - New tokens are stored after successful refresh All 12 new tests pass, confirming the core token refresh logic works as expected. This suggests issues reported in aws-amplify#14618 may be related to specific user configurations rather than the refresh mechanism itself. Co-Authored-By: Claude Opus 4.5 <[email protected]>
…fy#14618) Fix automatic token refresh failing silently when clockDrift is NaN. This addresses the issue where fetchAuthSession() does not auto-refresh expired tokens for CUSTOM_WITHOUT_SRP auth flow. ## Root Cause When clockDrift is NaN, the token expiration check always returns false: ```javascript // isTokenExpired.ts (before) return currentTime + clockDrift + tolerance > expiresAt; // currentTime + NaN + tolerance = NaN // NaN > expiresAt = false (always) ``` This causes expired tokens to never be detected as expired, preventing automatic refresh. ## How clockDrift becomes NaN In TokenStore.loadTokens(), clockDrift is parsed from storage: ```javascript const clockDriftString = (await storage.getItem(key)) ?? '0'; const clockDrift = Number.parseInt(clockDriftString); ``` The nullish coalescing operator (??) only handles null/undefined, not empty strings. If clockDrift is stored as "" (empty string): | Stored Value | ?? '0' result | parseInt() result | |--------------|---------------|-------------------| | null | '0' | 0 ✓ | | '123' | '123' | 123 ✓ | | '' | '' (falsy!) | NaN ✗ | This can happen with custom KeyValueStorage implementations or when certain auth flows don't properly initialize the clockDrift value. ## Fix Added three-layer defense against NaN clockDrift: 1. **TokenStore.ts**: Sanitize at load time ```javascript const parsedClockDrift = Number.parseInt(clockDriftString); const clockDrift = Number.isNaN(parsedClockDrift) ? 0 : parsedClockDrift; ``` 2. **TokenOrchestrator.ts**: Use || instead of ?? for fallback ```javascript clockDrift: tokens.clockDrift || 0 // NaN || 0 = 0 // vs clockDrift: tokens.clockDrift ?? 0 // NaN ?? 0 = NaN ``` 3. **isTokenExpired.ts**: Final safety net ```javascript const safeClockDrift = Number.isNaN(clockDrift) ? 0 : clockDrift; ``` ## Test Coverage Added comprehensive tests for clockDrift edge cases: - NaN clockDrift with expired tokens triggers refresh - NaN clockDrift with valid tokens does not trigger refresh - undefined clockDrift with expired tokens triggers refresh - Positive/negative/zero clockDrift handled correctly Co-Authored-By: Claude Opus 4.5 <[email protected]>
pgbezerra
requested review from
a team,
avi-karthik,
pranavosu and
sarayev
as code owners
This was referenced Jan 26, 2026
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NaNclockDrift valuesfetchAuthSession()does not auto-refresh expired tokens forCUSTOM_WITHOUT_SRPauth flowProblem
If
clockDriftwere to becomeNaN, the token expiration check would silently fail:This would cause expired tokens to never be detected as expired, preventing automatic refresh.
How clockDrift could become NaN
In
TokenStore.loadTokens(), clockDrift is parsed from storage:The nullish coalescing operator (
??) only handlesnull/undefined, not empty strings. IfclockDriftwere stored as""(empty string):?? '0'resultparseInt()resultnull'0'0✓'123''123'123✓''''(falsy!)NaN✗This could happen with custom
KeyValueStorageimplementations or if certain auth flows don't properly initialize theclockDriftvalue.Fix
Added defensive handling for
NaNclockDrift at multiple layers:||instead of??for fallback (NaN || 0 = 0vsNaN ?? 0 = NaN)NaNcheckRelated
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