[rush-lib] Add autoInstallPeers in pnpm-config

[Chao Guo (g-chao)]

Summary

PNPM8 changes the default value for auto-install-peers setting. It is default to true in
PNPM8

In this PR, we want to provide a option inside pnpm-config.json to let user overwrite auto-install-peers setting easily.

Details

If user set auto-install-peers in pnpm-config.json only, use the value in pnpm-config.json
If user set auto-install-peers in pnpm-config.json and .npmrc, use the value in pnpm-config.json, and output a warning message
If user set auto-install-peers in .npmrc only, do nothing, let pnpm handle it
If user does not set auto-install-peers in both pnpm-config.json and .npmrc, rush will default it to false

How it was tested

Manually tested on rush-example repo.

Impacted documentation

N/A

[Pete Gonzalez (octogonz)]

If user does not set auto-install-peers in pnpm-config.json and .npmrc, do nothing, let pnpm handle it

Ian Clanton-Thuon (@iclanton)Daniel (@D4N14L)David Michon (@dmichon-msft) Should Rush instead default to false? A couple considerations:

1. As with our reasoning regarding resolutionMode, a monorepo owner who is not following the latest PNPM news may innocently update pnpmVersion and be surprised to learn that installation semantics are suddenly very different from the past.
2. Is auto-install-peers=true an unwise choice for a large scale professional development? (The early discussions seemed to conclude that, but maybe opinions have changed?) We generally aim for Rush's out-of-box defaults to be the best choices for a large monorepo, even if that means diverging from the native defaults of PNPM.

[Pete Gonzalez (octogonz)]

🚀 This feature was released with Rush 5.109.1