Vite 3 - isProduction flipped to true in dev server after a production build

[bholmesdev]

Describe the bug

Our CI spins up a Vite dev server after running a production build. For some reason, plugins receive isProduction: true in their resolvedConfig, even when mode: 'development' is explicitly set in the dev server's inline config.

Reproduction

https://stackblitz.com/edit/github-u7wgc4?file=package.json

System Info

System:
    OS: macOS 12.2
    CPU: (8) x64 Apple M1 Pro
    Memory: 41.20 MB / 16.00 GB
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 14.18.1 - ~/.volta/tools/image/node/14.18.1/bin/node
    Yarn: 1.22.17 - ~/.volta/tools/image/yarn/1.22.17/bin/yarn
    npm: 8.4.0 - ~/.volta/tools/image/npm/8.4.0/bin/npm
  Browsers:
    Chrome: 103.0.5060.114
    Firefox: 102.0.1
    Safari: 15.3
  npmPackages:
    vite: 3.0.0-beta.10 => 3.0.0-beta.10

Used Package Manager

pnpm

Logs

No response

Validations

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• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Vite issue and not a framework-specific issue. For example, if it's a Vue SFC related bug, it should likely be reported to vuejs/core instead.
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• The provided reproduction is a minimal reproducible example of the bug.

[JoviDeCroock]

Hmm, this seems to be caused by the NODE_ENV being hard-set to production when running build, setting this persists across runs. 😅

• vite/packages/vite/src/node/config.ts

  Line 361 in f020066

  process.env.NODE_ENV = 'production'

• vite/packages/vite/src/node/config.ts

  Line 480 in f020066

  process.env.NODE_ENV = 'production'

Can PR something but not entirely sure what the preferred way forward is, I understand setting the env-variable but personally I would avoid it, I guess alternatively a fix would be to reset it post-build to the original value or account for mode: dev explicitly.

[bholmesdev]

@JoviDeCroock Worked out a PR with patak here! #9058
Seeing some nasty test runner issues though. Not sure what's going on there