gulp-concat discards errors from the stream

[markboyall]

We are using gulp-less to build our LESS files, then using gulp-concat to bundle them.

When we use concat, errors from LESS compilation are discarded. It seems that gulp-concat builds a result stream out of all of the incoming successful files; there is no handling for if the existing stream failed.

Our reproduction gulp task simlpy looks like

gulp.task('less', [], function () {
    return gulp
        .src(['./**/*.less', '!./node_modules/**'])
        .pipe(sourcemaps.init())
        .pipe(less({ paths: "./" }))
        .pipe(concat('styles.css'));
});