Mapped plugin relative paths break with commonjs require format

[jrburke]

Was requirejs/requirejs#640:

See test case here: The sample repo is here: https://github.com/guybedford/requirejs-plugin-map-bug

My notes from that ticket:

This is an interesting one. The cause: in node, there is an adapter module that provides a require.get() for synchronously loading a module, in case the request is for a node module that must be synchronously loaded. The problem line is here:
https://github.com/jrburke/r.js/blob/master/build/jslib/node.js#L62

and it is triggered by the require('coffee!./dep') call inside the module. However, .originalName, which is just the ./dep name, is called against the top level require, which ends up resolving relative to the baseUrl.

So, I need to reexamine that require.get() adapter. Another curious thing, the incoming moduleMap for that has an unnormalized module ID, but at that time the plugin should have already been loaded.

So, more investigation to do, but found the trigger. Marking for 2.1.5

[jrburke]

Related, map use, from @tbranyen:

var requirejs = require("requirejs");

requirejs.config({
  map: {
    "*": {
      "jquery": "cheerio"
    }
  }
});

requirejs.define("test", function(require) {
  var $ = require("jquery");
});

requirejs(["test"]);