Gulp-Sourcemaps SourcesContent null

Question

Using the following gulp syntax i'm trying to generate map files for our JS for debugging purposes.

gulp.task('useref', function () {
return gulp.src(['index.html'])
    .pipe(addStream.obj(prepareTemplates()))
    .pipe(useref())
    .pipe(versioning({
        'value': version,
        'append': {
            'key': 'v',
            'to': ['css', 'js'],
        },
        'replaces': [
            '#%releasenum%#'
        ]
    }))
    .pipe(sourcemaps.init({ loadMaps: true }))
    .pipe(gulpIf('*.js', uglify()))
    .pipe(sourcemaps.write('maps', {
        //sourceRoot: '',
        sourceMappingURLPrefix: domain,
        //debug: true
    }))
    .on('error', function (err) { gutil.log(gutil.colors.red('[Error]'), err.toString()); })
    .pipe(gulpIf('*.css', cssnano()))
    .pipe(gulp.dest('deploy'))
});

All the minification/bundling is done properly, however the map files contain a "sourcesContent:[null]" which i believe is preventing me from being able to properly use the map files.

I've been searching non stop but i cannot figure out how to have the map files contain the sourceContent correctly.

Our minified js files write to projectroot/deploy/app/*

Our map files write to projectroot/deploy/maps/*

The original unminified js files reside in projectroot/app/ .

When i run the debug:true on the sourcemaps.write I see:

gulp-sourcemap-write: No source content for "app/app.js". Loading from file.

gulp-sourcemap-write: No source content for "app/services.js". Loading from file.    
gulp-sourcemap-write: source file not found: C:\tfs\app\services.js

gulp-sourcemap-write: No source content for "app/controllers.js". Loading from file.
gulp-sourcemap-write: source file not found: C:\tfs\app\controllers.js

gulp-sourcemap-write: No source content for "app/directives.js". Loading from file.
gulp-sourcemap-write: source file not found: C:\tfs\app\directives.js

Answer 1

It ended up being gulp-uglify that was causing the issue. After downgrading to gulp-uglify 1.5.4 everything worked correctly.

Here is more information that helped me solve the problem: https://github.com/terinjokes/gulp-uglify/issues/236