Bug: Unexpected warning about persistentLogAttributes usage

[alex-karo]

Expected Behavior

The warning shouldn't appear if persistentLogAttributes is not used

Current Behavior

The warning appears if I pass persistentKeys into createChild function.

P.S. It works well if I call appendPersistentKeys separately

Code snippet

const logger = new Logger();
const child = logger.createChild({persistentKeys: {key: 'value'}});

Output:

{"level":"WARN","message":"Both persistentLogAttributes and persistentKeys options were provided. Using persistentKeys as persistentLogAttributes is deprecated and will be removed in future releases","timestamp":"2025-10-08T16:01:25.851Z","service":"service_undefined","sampling_rate":0,"key":"value"}

Steps to Reproduce

1. Create Logger
2. Create a child with persistentKeys param

Possible Solution

1. Do not set the default empty object to persistentLogAttributes
2. Or change the warning condition

Powertools for AWS Lambda (TypeScript) version

latest

AWS Lambda function runtime

22.x

Packaging format used

npm

Execution logs

[boring-cyborg]

Thanks for opening your first issue here! We'll come back to you as soon as we can.
In the meantime, check out the #typescript channel on our Powertools for AWS Lambda Discord: Invite link

[sdangol]

@alex-karo Thanks for creating the issue. We will put it to our backlog. If you would like to work on a fix for this, let me know and I can assign it to you. Otherwise, our team will pick it up in a few days.

[alex-karo]

@sdangol Yep, I can help with it

[sdangol]

Thanks! @alex-karo, I've assigned the issue to you now