Compilation errors are not handled properly

[fatfisz]

I was running grunt-contrib-watch with grunt-contrib-less and other tasks, and I noticed that only grunt-contrib-less was behaving strangely: if a compilation error was encountered, everything just hung up.

After long search through grount-contrib-watch and grunt I am fairly certain that the problem lies with how grunt-contrib-less handles compilation errors.

So in the less task there is a compileLess function, which contains this code at the end:

return less.render(srcCode, options)
  .catch(function(err) {
    lessError(err, srcFile);
  });

As you can see, in case of an error a message is printed, and then - because nothing is returned from the function in catch, the promise is fulfilled with undefined.

The next step is this then:

compileLess(file, destFile, options)
  .then(function(output) {
    compiled.push(output.css);
    ...

But it should be obvious by now that this throws an error, because output is undefined (compileLess was fulfilled with it) and we can't get the css property of undefined.

Because there are no further error handlers, the error is just sent into nothingness and the nextFileObj function is not called. This seems like something that is not desired.

I'm not sure what's the appropriate fix here. Would rethrowing the error be ok?

  .catch(function(err) {
    lessError(err, srcFile);
    throw err;
  });

[fatfisz]

@XhmikosR Could you check this out please? This is a very annoying problem. And I have a fix ready for this, so almost no work from the maintainers required.

[XhmikosR]

I'm still waiting for @vladikoff to look at #322 and then we can check #315.

[leigeber]

Would love to see this one merged in. Bites me every time. Is there something outstanding any of us can help resolve or is this still waiting on @vladikoff? Thanks.