NODE_ENV not inherited from .env file when running in a different mode

[RickMeijer]

Version

3.7.0

Reproduction link

https://github.com/RickMeijer/bugreport-vuecli-environment

Environment info

  System:
    OS: macOS Mojave 10.14.4
    CPU: (8) x64 Intel(R) Core(TM) i7-7820HQ CPU @ 2.90GHz
  Binaries:
    Node: 10.13.0 - ~/.nvm/versions/node/v10.13.0/bin/node
    Yarn: 1.15.2 - /usr/local/bin/yarn
    npm: 6.9.0 - ~/.nvm/versions/node/v10.13.0/bin/npm
  Browsers:
    Chrome: 74.0.3729.131
    Firefox: 66.0.3
    Safari: 12.1
  npmGlobalPackages:
    @vue/cli: 3.7.0

Steps to reproduce

Either:

• Clone project
• npm run build
• npm run build -- --mode=foo

Or:

• Create new project
• Create .env
• In the .env file, set NODE_ENV to production
• Create empty .env.foo
• Run npm run build -- --mode=foo

What is expected?

NODE_ENV should be 'production'

According to the docs; all environments load the .env file. That should mean it also inherits the variables set therin.

What is actually happening?

NODE_ENV is 'development'

[RickMeijer]

When setting NODE_ENV in the [mode] file, everything works as expected.
It becomes impossible to set a default though, contrary to every other environment variable.

[novbing]

According to the official wiki, when you do npm run serve without --mode, it neans --mode=development. So process.env.NODE_ENV is 'development', even though you define it production in .env.

In this case, you can make a .env.development like below:

NODE_ENV=production
TITLE=inheritance works (from .env.development)

Then do npm run serve output console:
Current build environment is production
Fortunately, inheritance works (from .env.development)

wiki:
https://cli.vuejs.org/guide/cli-service.html#vue-cli-service-serve
https://cli.vuejs.org/guide/mode-and-env.html#modes

[makraz]

Vue-cli Version: 3.7.0
Environment info
System:
OS: macOS Catalina 10.15.2
Binaries:
Node: v12.14.0
Yarn: 1.21.1
npm: 6.13.4
Browsers:
Chrome: Version 78.0.3904.108 (Official Build) (64-bit)

I have the same issue NODE_ENV not inherited from .env file when running in a different mode
but when i restart system and again the command take the env config

Scenario

I run build with : npm run build -- --mode development
the build done successfully after that i run the build with npm run build (also i tried npm run build -- --mode production)
the build done successfully but all config is inherited from .env.development and not from .env. production
but if i restart the system again and run npm run build (or npm run build -- --mode production) the build done successfully and it's work fine

so what i think is that the config is loaded on the RAM and when the mode is change vue-cli done update config in RAM