[BUG] `npm explain` on repo with large # of packages fails with `invalid string length`

Is there an existing issue for this?

• I have searched the existing issues

This issue exists in the latest npm version

• I am using the latest npm

Current Behavior

In a monorepo with a large number of packages in an npm workspace, the npm explain command fails to return.

Expected Behavior

A more useful error should be returned, or the output format of npm explain should be amended to make the output smaller and more useful.

For the other corepack package managers:

• yarn why returns a compact output and succeeds
• pnpm why crashes with heap out of memory errors

Steps To Reproduce

1. In my reproduction repository: https://github.com/forivall/npm-explain-invalid-string-length-repro
2. Run npm explain yargs or npm explain yargs --json
3. See the error npm ERR! Invalid string length
   • or, with --json, we see

      npm ERR! Invalid string length
      {
        "error": {
          "code": null,
          "summary": "Invalid string length",
          "detail": ""
        }
      }
     

Environment

• npm: 8.19.4
• Node.js: v16.17.0
• OS Name: macOS 13.3.1
• System Model Name: Macbook Pro
• npm config:

; "user" config from /Users/emily.klassen/.npmrc

//registry.npmjs.org/:_authToken = (protected)
email = "forivall@gmail.com"
init-author-name = "emily"
legacy-peer-deps = true

; node bin location = /Users/emily.klassen/.nvm/versions/node/v16.17.0/bin/node
; node version = v16.17.0
; npm local prefix = /Users/emily.klassen/code/public/npm-explain-invalid-string-length-repro
; npm version = 8.19.4
; cwd = /Users/emily.klassen/code/public/npm-explain-invalid-string-length-repro
; HOME = /Users/emily.klassen
; Run `npm config ls -l` to show all defaults.

Start by reproducing the failure in the linked npm-explain-invalid-string-length-repro repository with npm explain yargs and npm explain yargs --json. Trace the npm explain CLI path involved in producing the oversized output. Done means the command no longer fails with Invalid string length and returns either a useful error or smaller, more useful output.