fix(pino-logging-gcp-config): log mutates input

[tohalla]

formatLogObject mutates input

Pino supports passing mergingObject as the first parameter for logging. Current implementation mutates the passed object instead of its copy (e.g. https://github.com/pinojs/pino/blob/116b1b17935630b97222fbfd1c053d199d18ca4b/test/formatters.test.js#L85).

We noticed the issue as we had request body passed as the first argument to pino logging.

Expected behaviour

const obj = {foo: "bar"}
pino(createGcpLoggingPinoConfig(
  { serviceContext: { service: "..." } },
  {},
)).info(obj)
// obj is still {foo: 'bar'}

Current behaviour

const obj = {foo: "bar"}
pino(createGcpLoggingPinoConfig(
  { serviceContext: { service: "..." } },
  {},
)).info(obj)
// obj is now {
//   foo: 'bar',
//   serviceContext: { service: '...' },
//   'logging.googleapis.com/insertId': '...'
// }

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[nielm]

Thank you for this PR.

[nielm]

fixed in v 1.0.5
https://www.npmjs.com/package/@google-cloud/pino-logging-gcp-config/v/1.0.5

[nielm]

Apologies - v1.0.5 was built against an older version of the code without this fix - please use newly released 1.0.6