[Bug?]: `yarn config set` reformats quoting in `.yarnrc.yml`

[GideonPARANOID]

Self-service

• I'd be willing to implement a fix

Describe the bug

I have a .yarnrc.yml which matches the rest of our project's style rules - using single quotes by default.

However, when setting additional config in the file via yarn config set, the quoting gets changed for all properties.

This is problematic in CI in my projects, as we need to set auth tokens from CI secrets storage, & then linting is ran, which fails due to the change in format style.

To reproduce

[gideonparanoid]:[~/workspace/node]:[main] cat .yarnrc.yml
npmScopes:
  test:
    npmRegistryServer: 'https://test.com'
[gideonparanoid]:[~/workspace/node]:[main] yarn config set "npmRegistries['//test.com'].npmAuthToken" 'value'
➤ YN0000: Successfully set npmRegistries["//test.com"].npmAuthToken to '********'
[gideonparanoid]:[~/workspace/node]:[main] cat .yarnrc.yml
npmRegistries:
  //test.com:
    npmAuthToken: value

npmScopes:
  test:
    npmRegistryServer: "https://test.com"

Environment

System:
    OS: macOS 26.0.1
    CPU: (10) arm64 Apple M1 Pro
  Binaries:
    Node: 24.11.1 - /private/var/folders/4d/cfz93ltx1hj8sd0gnnq7mvlc0000gn/T/xfs-ca46317a/node
    Yarn: 4.12.0 - /private/var/folders/4d/cfz93ltx1hj8sd0gnnq7mvlc0000gn/T/xfs-ca46317a/yarn
    npm: 11.6.2 - /Users/Gideon.Jones/.nvm/versions/node/v24.11.1/bin/npm

Additional context

No response

[GideonPARANOID]

FWIW, I am managing with a workaround by using:

echo -e "\nnpmRegistries:\n  //test.com/:\n    npmAuthToken: value" >> .yarnrc.yml

This is obviously not as adaptable.