Non-dead code removed

[raybooysen]

Not sure if this is an uglifyify problem or an uglify problem, but we're seeing cases where non-dead code is dropped. Consider the following:

var result
var useX = //some code here;
if(useX) {
  result = require('./someotherModuleX');
} 
else {
 result = require('./someotherModuleY');
}
module.exports = result;

When we run this through uglifyify, both someOtherModuleX and someOtherModuleY are removed.

However, this works:

var useX = //some code here;
if(useX) {
  module.exports = require('./someotherModuleX');
} 
else {
 module.exports = require('./someotherModuleY');
}

A sample app is here:

https://github.com/raybooysen/uglifyifyExample

[weilu]

It's a strange case -- I inspected the buffer value before ujs.minify is even called: https://github.com/hughsk/uglifyify/blob/master/index.js#L70. It's already missing the two required files. Pushed the failing test case to a branch: cd38bb4

@hughsk browserify bug?