prettier incompatibility with npm 12

[klafbang]

I use spotless 3.10.0 with npm + node installed via maven frontend for CI.

When running with npm 11.19.0 it works fine, but when I upgrade to npm 12.0.2, at least prettier fails with

Aug 19 22:06:00 [INFO] [BEGIN] Starting npm based server in /Users/michael/java/pairwise-comparison/target/spotless-prettier-node-modules-1cf7fada45e1395505a647d448bc2252 with StandardNpmProcessFactory.
Aug 19 22:06:00 [INFO] [END] Starting npm based server in /Users/michael/java/pairwise-comparison/target/spotless-prettier-node-modules-1cf7fada45e1395505a647d448bc2252 with StandardNpmProcessFactory. (took 4ms)
Aug 19 22:07:00 [INFO] creating formatter function (starting server)
Aug 19 22:07:00 [INFO] [BEGIN] Starting npm based server in /Users/michael/java/pairwise-comparison/target/spotless-prettier-node-modules-1cf7fada45e1395505a647d448bc2252 with StandardNpmProcessFactory.
Aug 19 22:07:01 [INFO] [END] Starting npm based server in /Users/michael/java/pairwise-comparison/target/spotless-prettier-node-modules-1cf7fada45e1395505a647d448bc2252 with StandardNpmProcessFactory. (took 11ms)
Aug 19 22:08:01 [INFO] creating formatter function (starting server)
Aug 19 22:08:01 [INFO] [BEGIN] Starting npm based server in /Users/michael/java/pairwise-comparison/target/spotless-prettier-node-modules-1cf7fada45e1395505a647d448bc2252 with StandardNpmProcessFactory.
Aug 19 22:08:01 [INFO] [END] Starting npm based server in /Users/michael/java/pairwise-comparison/target/spotless-prettier-node-modules-1cf7fada45e1395505a647d448bc2252 with StandardNpmProcessFactory. (took 5ms)

or, it doesn't so much fail as it just keeps trying to start prettier using npm every minute. I don't know if the same is true of other npm-based modules.

The slop machine suggests that Spotless launches using --scripts-prepend-node-path=true when using an absolute path. I tried this manually on npm 11 and 12.

For npm 11 (system npm):

# npm run start --scripts-prepend-node-path=true -- --node-server-instance-id=test1

npm warn Unknown cli config "--scripts-prepend-node-path". This will stop working in the next major version of npm.

> spotless-prettier@4.0.1 start
> node serve.js --node-server-instance-id=test1

For npm 12 (installed via maven frontend):

# ../../target/node/npm run start --scripts-prepend-node-path=true -- --node-server-instance-id=test2

npm error code EUNKNOWNCONFIG
npm error Unknown cli flag:
npm error   - --scripts-prepend-node-path
npm error Run `npm help config` for supported options.
npm error A complete log of this run can be found in: /Users/michael/.npm/_logs/2026-08-19T20_18_10_194Z-debug-0.log

So, if the slop machine is correct, that seems to explain the behavior: the option was removed in or before 11, and causes termination in 12.