.env values override existing env vars when using --watch

[tandibar]

If you start a fastify app with the fastify cli and the watch parameter, the environment variable precedence is changed.

Example

So if you have a .env file with

MY_ENV_VAR=foo

and you run

MY_ENV_VAR=bar fastify start app.js

then process.env.MY_ENV_VAR will be 'bar'. Perfect! But if you run it with the watch parameter like

MY_ENV_VAR=bar fastify start --watch app.js

then process.env.MY_ENV_VAR will be 'foo'.

Suggestion

I think it has something to do with this line of code.