doc, test: update --watch for linux recursive watch

[RedYetiDev]

Follow-up #45098

This PR removes the unused error code ERR_FEATURE_UNAVAILABLE_ON_PLATFORM, and stops skipping some of the watch mode tests on Linux machines.

[richardlau]

I'm a bit surprised ERR_FEATURE_UNAVAILABLE_ON_PLATFORM is now unused -- I was under the impression that watch mode still doesn't work on e.g. IBM i (most watch tests skip) and at one point that error was returned there.

cc @nodejs/platform-ibmi

[RedYetiDev]

If you search for the error, it's only mentioned in the docs and defined in errors.js, it is never thrown.

[richardlau]

If you search for the error, it's only mentioned in the docs and defined in errors.js, it is never thrown.

I can see that, but I'm questioning whether the code was changed to not throw the error anymore on all platforms despite watch not working on IBM i -- AFAIK it's a system limitation there.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.41%. Comparing base (1d5ed72) to head (a0719b8).
Report is 237 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #55256      +/-   ##
==========================================
- Coverage   88.41%   88.41%   -0.01%     
==========================================
  Files         652      652              
  Lines      186572   186585      +13     
  Branches    36045    36061      +16     
==========================================
+ Hits       164957   164967      +10     
+ Misses      14899    14887      -12     
- Partials     6716     6731      +15     

Files with missing lines	Coverage Δ
lib/internal/errors.js	96.98% <ø> (-0.01%)	⬇️

... and 49 files with indirect coverage changes

[RedYetiDev]

FWIW the tests are skipped on IBMi

[abmusse]

@richardlau

Looks like calling fs.watch on IBM i returns ENOSYS.

const fs = require('fs');

fs.watch('dummy', (eventType, filename) => {
  console.log(`event type is: ${eventType}`);
  if (filename) {
    console.log(`filename provided: ${filename}`);
  } else {
    console.log('filename not provided');
  }
});

Error: ENOSYS: function not implemented, watch 'dummy'

I'm not sure if ever returned ERR_FEATURE_UNAVAILABLE_ON_PLATFORM in the past but currently ENOSYS is being returned.

[richardlau]

Maybe I misremembered then. 🤷

[RedYetiDev]

I've added https://github.com/nodejs/node/labels/dont-land-on-v18.x as #45098 didn't land on that release line. If you could review it would be appreciated :-)