11

Gulp 3 から 4 にアップグレードしていますが、次のエラーが発生します。

The following tasks did not complete: build
Did you forget to signal async completion?

言っていることは理解できますが、なぜこのコードがトリガーされているのか理解できません。

エラーの有無にかかわらず、タスクは完了します (ファイルは連結され、dest に書き込まれます)。lazypipe を使用せずに同じコードを実行してもエラーは発生せず、lazypipe 内の連結を削除してもエラーは修正されます。

ストリームを作成するもの (merge-stream など) で全体をラップすると、問題が修正されます。gulp-concat と lazypipe の間の相互作用に関する何かが、ストリームが正しく返されないようになっていると思います。

（簡略化された）タスクは次のとおりです。

gulp.task('build', function() {
    var dest = 'build';

    var buildFiles = lazypipe()
        .pipe(plugins.concat, 'cat.js') // Task will complete if I remove this
        .pipe(gulp.dest, dest);

    // This works
    // return gulp.src(src('js/**/*.js'))
    //     .pipe(plugins.concat('cat.js'))
    //     .pipe(gulp.dest(dest));

    // This doesn't (unless you wrap it in a stream-making function)
    return gulp.src(src('js/**/*.js'))
        .pipe(buildFiles());
});

アドバイスをいただければ幸いです。

4

2 に答える 2

14

This is a known issue when using lazypipe with gulp 4 and it's not going to be fixed in the near future. Quote from that issue:

OverZealous commented on 20 Dec 2015
As of now, I have no intention of making lazypipe work on Gulp 4.

As far as I can tell this issue is caused by the fact that gulp 4 uses async-done which has this to say about its stream support:

Note: Only actual streams are supported, not faux-streams; Therefore, modules like event-stream are not supported.

When you use lazypipe() as the last pipe what you get is a stream that doesn't have a lot of the properties that you usually have when working with streams in gulp. You can see this for yourself by logging the streams:

// console output shows lots of properties
console.log(gulp.src(src('js/**/*.js'))
  .pipe(plugins.concat('cat.js'))
  .pipe(gulp.dest(dest))); 

// console output shows much fewer properties
console.log(gulp.src(src('js/**/*.js'))
  .pipe(buildFiles()));

This is probably the reason why gulp considers the second stream to be a "faux-stream" and doesn't properly detect when the stream has finished.

Your only option at this point is some kind of workaround. The easiest workaround (which doesn't require any additional packages) is to just add a callback function cb to your task and listen for the 'end' event:

gulp.task('build', function(cb) {
  var dest = 'build';

  var buildFiles = lazypipe()
   .pipe(plugins.concat, 'cat.js') 
   .pipe(gulp.dest, dest);

  gulp.src(src('js/**/*.js'))
   .pipe(buildFiles())
   .on('end', cb);
});

Alternatively, adding any .pipe() after buildFiles() should fix this, even one that doesn't actually do anything like gutil.noop():

var gutil = require('gulp-util');

gulp.task('build', function() {
  var dest = 'build';

  var buildFiles = lazypipe()
    .pipe(plugins.concat, 'cat.js') 
    .pipe(gulp.dest, dest);

  return gulp.src(src('js/**/*.js'))
    .pipe(buildFiles())
    .pipe(gutil.noop());
});
于 2016-10-18T06:50:43.330 に答える