grunt.util.error rendering

[emilbayes]

A colleague (@sp90) and I were adding error output from a terminal tool to a Grunt task, for Grunt to pass on to the user. The task is async and something along the lines of this:

grunt.registerMultiTask('terminal-task', 'Execute some terminal tool', function() {
   var done = this.async();

   this.files.forEachAsync(function(file, idx, next) {
      grunt.spawn({
         cmd: 'sometool',
         args: [file]
      }, function(err, res) {
         if(err !== null) return next(grunt.util.error(err));
         //Do something with res
         next();
      });
   }, done);

What we were surprised to see was that the error was not rendered by Grunt like grunt.log.error, which is what we expected, but rendered like grunt.log.warn. I tried to dig through the commit log, but didn't see anything about this being a conscious decision. The closest I found was #1163, but is in my opinion only tangentially related.

The relevant lines are lib/util/task.js#L220-L222 -> lib/grunt.js#L136-L138 -> lib/grunt/fail.js#L28-L40

What I want to know is:

• is this intended behaviour or legacy?
• Can/should we fix this?
• Is grunt.util.error meant to be used like this?