fix: inline completions fail with TypeError under IAM auth due to string expiration

[laileni-aws]

Problem

When the language server runs with IAM authentication (the mode used by hosted notebook / cloud IDE environments), every inline completion request fails before reaching the network with:

TypeError: identity.expiration.getTime is not a function

Cause: IAM credentials are pushed to the server over JSON, so the expiration field arrives as an ISO string, not a Date. CodeWhispererServiceIAM's SDK credential callback passed it straight through:

return { accessKeyId: creds.accessKeyId, secretAccessKey: ..., sessionToken: ..., expiration: creds.expiration }

@smithy/core's memoized identity provider then calls identity.expiration.getTime() to decide whether the credentials need refreshing, which throws on a string. Because this happens inside generateSuggestions(), the inline-completion handler records a failed service invocation (CodeWhisperer Invocation Exception: TypeError, duration ≈ 0) on every auto-triggered completion — i.e. on every keystroke — for every IAM-authenticated user.

The streaming (chat) IAM client already handles this correctly (expiration: creds.expiration ? new Date(creds.expiration) : new Date() in StreamingClientServiceIAM), which is why chat works under IAM auth while inline completions do not. The inline client lost its equivalent handling in the aws-sdk v2 → v3 migration.

A second, related gap on the same path: AmazonQIAMServiceManager.getCodewhispererService() never checked whether IAM credentials had been pushed at all, so the same callback also threw TypeError: Cannot read properties of undefined while credentials were absent (startup ordering, failed refresh, credentials-delete). The token-based manager already guards this with AmazonQServicePendingSigninError. The existing unit tests in AmazonQIAMServiceManager.test.ts asserted that guard but were failing because it was never implemented.

Solution

1. CodeWhispererServiceIAM credential callback — convert expiration with new Date(creds.expiration) (undefined stays undefined), matching StreamingClientServiceIAM. This is the fix for the persistent TypeError under IAM auth.
2. Same callback — validate the credentials object and throw Error('Authorization failed, IAM credentials are not set') when it is missing or incomplete, matching the bearer provider's contract.
3. AmazonQIAMServiceManager.getCodewhispererService() — throw AmazonQServicePendingSigninError('No IAM credentials available') when hasValidCredentials() is false, mirroring the token manager, so a not-yet-authenticated state exits the inline handler before a session is created (no failed-invocation telemetry), exactly as the bearer path behaves today.
4. Tests — regression test that a string expiration is returned as a Date and getTime() works (fails without the fix); tests for missing/incomplete credentials producing a non-TypeError authorization error; fix the two existing manager tests and add a test that no service is created while credentials are missing and that it is created once they arrive.

No change to behaviour when credentials are present and already a Date.

Testing

• ts-mocha src/shared/amazonQServiceManager/AmazonQIAMServiceManager.test.ts src/shared/codeWhispererService.test.ts: 23 passing. The 3 remaining failures in codeWhispererService.test.ts (CodeWhispererServiceToken … this.client.send is not a function) are pre-existing on main and unrelated.
• Verified the string-expiration TypeError directly against @smithy/core.memoizeIdentityProvider with a string vs. Date expiration.
• tsc --noEmit clean; prettier --check clean; eslint only pre-existing warnings.

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

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Codecov Report

❌ Patch coverage is 40.90909% with 13 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...p-codewhisperer/src/shared/codeWhispererService.ts	0.00%	10 Missing ⚠️
.../amazonQServiceManager/AmazonQIAMServiceManager.ts	75.00%	3 Missing ⚠️

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