segmentio/metalsmith — pull request #12 by andrewk (2014-03-10 02:29:12+00:00)
Title: Example code fails silently due to plugins

Same as https://github.com/segmentio/metalsmith.io/pull/5

If plugins are required and passed in to `#use` without having their constructor called, the metalsmith `#build` method fails silently.

eg:

```js
var Metalsmith = require('metalsmith')
, markdown = require('metalsmith-markdown');

Metalsmith(__dirname)
.use(markdown)
.build(function(err) {
console.log('This will never be printed');
});
```

Is it potentially worth storing a hash of plugin methods registered to be called and then error on `build` if they haven't all been called, signifying one in the `use` chain failed to call `next`?