A single task in gulp.watch() using gulp.task() incorrectly logs as <anonymous>

[jaydenseric]

As discussed earlier.

Using the latest version of Gulp 4:

var gulp = require('gulp');

gulp.task('css', function () {
  return gulp.src('test.css');
});

gulp.task('watch', function () {
  gulp.watch('test.css', gulp.task('css'))
})

Results in:

[09:45:21] Starting 'watch'...
[09:45:24] Starting '<anonymous>'...
[09:45:24] Finished '<anonymous>' after 15 ms

Whereas replacing the watch task with:

gulp.task('watch', function () {
  gulp.watch('test.css', gulp.registry().get('css'))
})

Results in:

[09:52:17] Starting 'watch'...
[09:52:20] Starting 'css'...
[09:52:20] Finished 'css' after 16 ms

[axvm]

gulp.task() returns function which in fact anonymous (function() { }).

gulp.task():

function task(name, fn) {
  if (typeof name === 'function') {
    fn = name;
    name = fn.displayName || fn.name;
  }

  if (!fn) {
    return this._getTask(name);
  }

  this._setTask(name, fn);
}

gulp._getTask():

function get(name) {
  var wrapper = this._registry.get(name);

  if (!wrapper) {
    return;
  }

  var meta = metadata.get(wrapper);

  if (meta) {
    return meta.orig; // Here is our anonymous function, Watson!
  }

  return wrapper;
}

The problem can be resolved by overriding _getTask method in gulp/index.js like this:

  var metadata = require('undertaker/lib/helpers/metadata');

  function Gulp() {
    // ... 
    this._getTask = function get(name) {
      var wrapper = this._registry.get(name);

      if (!wrapper) {
        return;
      }

      var meta = metadata.get(wrapper);

      if (meta) {
        let orig = meta.orig;
        orig.displayName = meta.name;

        return orig;
      }

      return wrapper;
    };
  }

Yea, this is private method but another way to fix the problem - override gulp.task

[phated]

@avxm it just needs to be fixed in undertaker.

[axvm]

@phated I can send PR. But which way preferred? Set function displayName in public task method or in private _getTask method?

[phated]

Neither, gulp shouldn't modify a user's function. I'm not sure of the complete solution for this. It might need to be done with the watch debounce changes.

[axvm]

@phated I don't understand why we can't set displayName if it undefined?

example from PR:

 fn.displayName = fn.displayName || 'foo'

We do not modify value if it defined. Also i'm not sure with decision to fix it in undertaker. This is project-specific problem so it needs to be fixed here, isn't?

[axvm]

Ok. Now I understand why it needs to be fixed in undertaker and why we shouldn't modify user's functions. Anyways the problem in return value of task method. Any pros why it must to return unwrapped function?

[phated]

I had some time to look into this and I couldn't come up with a good reason why I wanted to return the unwrapped function. Instead, gulp.task('taskName') will return the wrapped function with an unwrap() method if you need to get the original function. I have the code, just need to finish it up and push it.

[phated]

@jaydenseric @axvm this should be fixed by my update of undertaker in d8f5c90