Cache-busting scheme incompatible with r.js (require.js)? - requirejs

Question

In my application, I want to have an environment config that uses a different version name for every deploy so that the application is properly cache busted and users don't have stale versions of code in their browser cache. Note I have been following this guide.
Thus, in main.js, before I do anything, I call require.config with a generic config that uses the current date/time to bust the cache on the environment config file, then after the environment config is loaded, I use the environment "config.version" as part of the urlArgs to guarantee that the newly deployed code is included and not a stale version. Note that the object from the config file has other properties that will be used throughout the application as well (e.g. google analytics account number).
It seems that my r.js build file is fine if I remove the first require.config that allows me to setup the environment/config dependency, but when I add it back in, the infrastructure JS module that I'm using to group third-party scripts chokes saying it can't find my underscore lib (or any lib I include in there for that matter). Note that even if I don't include environment/config and just make the two require.config calls, the same error results. Is there a reason two require.config calls would cause this error? Thanks for any help.
//Error:
Error: ENOENT, no such file or directory '<%root_folder%>\dist\js\underscore.js'
In module tree:
infrastructure
My main JS file
//main.js
require.config({
baseUrl: "js",
waitSeconds: 0,
urlArgs: "bustCache=" + (new Date).getTime()
});
require(["environment/config"], function(config) {
"use strict";
require.config({
urlArgs: "bustCache=" + config.version,
baseUrl: "js",
waitSeconds: 0,
paths: {
underscore: "lib/lodash.underscore-2.4.1-min",
},
shim: {
"underscore":{
exports : "_"
}
}
});
//commented out, b/c not needed to produce the error
//require(["jquery", "infrastructure"], function($) {
//$(function() {
//require(["app/main"], function(app) {
//app.initialize();
//})
//});
//});
});
And here's the build file...
//build file
({
mainConfigFile : "js/main.js",
appDir: "./",
baseUrl: "js",
removeCombined: true,
findNestedDependencies: true,
dir: "dist",
optimizeCss: "standard",
modules: [
{
name: "main",
exclude: [
"infrastructure"
]
},
{
name: "infrastructure"
}
],
paths: {
"cdn-jquery": "empty:",
"jquery":"empty:",
"bootstrap.min": "empty:"
}
})
Here infrastructure.js
define(["underscore"], function(){});
config file (will have more keys like google analytics account number and other environment specific info.)
//config.js
define({version:"VERSION-XXXX", cdn: { jquery: "//path-to-jquery-1.11.0.min" }});
command I'm running: "r.js -o build.js"

Answer 1

Ok, yes, it is a problem with the two require.config calls. At runtime, there is absolutely no problem calling config multiple times. However, at build time, r.js is not able to follow the calls. So if your build depends on any later call to require.config you are going to have problems.
I see that your second call to require.config does not contain any value that is computed on the basis of what is loaded after the first call, except for urlArgs so you could move everything from that second call into the first one, except for urlArgs.