Global serializer invoked on child creation

Description

'use strict'

const pino = require('pino')

const logger = pino({
  useLevelLabels: true,
  messageKey: 'message',
  base: null,
  serializers: {
    [Symbol.for('pino.*')]: obj => {
      console.log('serializer')
      console.log(obj);
      return obj
    },
    
    err: (obj) => {
      console.log('err serializer')
      return obj
    }
  }
});

let l = logger.child({ app: {
  name: 'blah'
}})

serializer
{ app: { name: 'blah' } }

Contributor guide

Tech stack

javascriptnodejs

Domain

backend

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

stale

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

Node.js basicsPino logger basics

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

40

Research direction

Investigate the pino child creation flow in the source code, specifically the 'child' method in pino.js. The issue suggests that the wildcard serializer (Symbol.for('pino.*')) is being applied during child creation rather than at log time. Look at how serializers are merged in child() and ensure they are only invoked when a logging function (e.g., info, error) is called. Check existing tests related to serializers and child loggers to understand expected behavior.