DeprecationWarning: Invalid 'main' field in [...]/gatsby/dist/internal-plugins/functions/package.json' of 'index.ts'

[Hahlh]

Description

After a migration from v2 to v3 and fighting through a jungle of dependency conflicts, I finally arrived at a successful build.

There were (are) 3 deprecation warnings:

1. DeprecationWarning: OutgoingMessage.prototype._headers is deprecated
2. DeprecationWarning: Use of deprecated folder mapping "./" in the "exports" field module resolution of the package at [...]/]tslib/package.json. Update this package.json to use a subpath pattern like "./*".
3. DeprecationWarning: Invalid 'main' field in [...]/gatsby/dist/internal-plugins/functions/package.json' of 'index.ts'
   ([...] omitted for readability)

Number one got solved by manually npm i got@latest.

The other two still persist.

This issue is meant to document number three as there apparently aren't any related issues so far.
The others are included for context.

Functions aren't used within the project (besides Netlify functions).

Environment:

  System:
    OS: Linux 5.10 Manjaro Linux
    CPU: (16) x64 AMD Ryzen 7 4800H with Radeon Graphics
    Shell: 5.8 - /usr/bin/zsh
  Binaries:
    Node: 16.1.0 - /usr/bin/node
    Yarn: 1.22.10 - ~/.npm-packages/bin/yarn
    npm: 7.12.1 - /usr/bin/npm
  Languages:
    Python: 3.9.5 - /usr/bin/python
  Browsers:
    Firefox: 89.0
  npmPackages:
    gatsby: ^3.7.0 => 3.7.0 
    gatsby-background-image: ^1.5.3 => 1.5.3 
    gatsby-image: ^3.7.0 => 3.7.0 
    gatsby-plugin-anchor-links: ^1.2.1 => 1.2.1 
    gatsby-plugin-gdpr-cookies: ^2.0.1 => 2.0.1 
    gatsby-plugin-image: ^1.7.0 => 1.7.0 
    gatsby-plugin-manifest: ^3.7.0 => 3.7.0 
    gatsby-plugin-netlify: ^3.7.0 => 3.7.0 
    gatsby-plugin-postcss: ^4.7.0 => 4.7.0 
    gatsby-plugin-preact: ^5.7.0 => 5.7.0 
    gatsby-plugin-preconnect: ^1.2.0 => 1.2.0 
    gatsby-plugin-react-helmet: ^4.7.0 => 4.7.0 
    gatsby-plugin-remove-fingerprints: 0.0.2 => 0.0.2 
    gatsby-plugin-sass: ^4.7.0 => 4.7.0 
    gatsby-plugin-scroll-reveal: 0.0.7 => 0.0.7 
    gatsby-plugin-sharp: ^3.7.0 => 3.7.0 
    gatsby-plugin-transition-link: ^1.20.5 => 1.20.5 
    gatsby-plugin-webpack-bundle-analyser-v2: ^1.1.22 => 1.1.22 
    gatsby-source-filesystem: ^3.7.0 => 3.7.0 
    gatsby-source-prismic: ^3.3.6 => 3.3.6 
    gatsby-transformer-remark: ^4.4.0 => 4.4.0 
    gatsby-transformer-sharp: ^3.7.0 => 3.7.0 
  npmGlobalPackages:
    gatsby-cli: 3.6.0

I just got message #3 after updating today. Also no serverless functions for this project.

Ubuntu 20.04
Node v16.3.0
npm 7.15.1
Gatsby 3.7.1
Gatsby CLI 3.7.0

[t2ca]

I've seen these warnings for a little while now. I'm also getting this other one.

(node:40233) [DEP0148] DeprecationWarning: Use of
deprecated folder mapping "./" in the "exports" field
module resolution of the package at
/node_modules/gatsby/node_modules/postcss/package.json.
Update this package.json to use a subpath pattern like "./*".