A "nestedKeyName: {}" is always added to the log and displayed by pretty even if there is nothing to nest

[frzsombor]

If I set the nestedKey: payload option, the nested key is always added to the log and pino-pretty also displays it every time, even if I try to log a simple string (and if I can remember correctly, this was not the case with v6).

A simple logger.info('info'); makes pino-pretty (with base: undefined, timestamp: pino.stdTimeFunctions.isoTime options) show the following:

[2021-10-17T17:52:12.208Z] INFO: info
    payload: {}

---

My current workaround:
Right now I'm using the following hook method to achieve similar results as v6 (only wrap object if necessary):

hooks: {
    logMethod (inputArgs, method, level) {
        if (typeof inputArgs[0] !== 'string' && !(inputArgs[0] instanceof Error)) {
            return method.apply(this, [ { object: inputArgs[0] } ]);
        }
        return method.apply(this, inputArgs);
    }
},

[mcollina]

This looks like a bug. Would you like to send a PR to fix it?

[frzsombor]

I actually tried to fix this in the code too, but I could not decide if it is a problem in proto.js here or I should simply add an additional check in tools.js here. That's all I've found.

[mcollina]

probably in the line with mixin defined.

If that's the case this ha not been introduced in v7, what's the latesr version this was working for you?

[frzsombor]

For me, it definitely looks like a v7 related change/bug.
Simple test:

const logger = require('pino')({nestedKey:'nest'});
logger.info({asd:'1'});
logger.info('hello');

pino v6.13.3 results:

{"level":30,"time":1634576867070,"pid":41448,"hostname":"x","nest":{"asd":"1"}}
{"level":30,"time":1634576867071,"pid":41448,"hostname":"x","msg":"hello"}

pino v7.0.2 results:

{"level":30,"time":1634577116365,"pid":41717,"hostname":"x","nest":{"asd":"1"}}
{"level":30,"time":1634577116365,"pid":41717,"hostname":"x","nest":{},"msg":"hello"}  <- 'nest' added in v7

[mcollina]

Would you like to send a Pull Request to address this issue? Remember to add unit tests.

[frzsombor]

I would be happy to help, but I think this task might require a deeper understanding of the codebase that I currently have in this project.

[simoneb]

A git bisect shows that this behavior was introduced in #885

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.