[BUGFIX Release] Add warning for addons missing project

Some addons may not have been instantiated correctly (for latest CoreObject)
This detects a common failure mode. Hopefully this helps us catch and
upgrade these addons quickly.

lib/models/addon.js

@@ -283,6 +283,10 @@ var Addon = CoreObject.extend({
   */
   treeGenerator: function(dir) {
     var tree;
+
+    if (!this.project) {
+      console.warn('Addon: `' + this.name + '` is missing addon.project, this may be the result of an addon forgetting to invoke `super` in its init.');
+    }
     // TODO: fix law of demeter `_watchmanInfo.canNestRoots` is obviously a poor idea
     if ((this.project && this.project._watchmanInfo.canNestRoots) ||
         this.isDevelopingAddon()) {

tests/unit/models/addon-test.js

@@ -32,14 +32,26 @@ describe('models/addon.js', function() {
   });
 
   describe('old core object compat', function() {
+    var oldWarn = console.warn;
+
+    after(function() {
+      console.warn = oldWarn;
+    });
+
     it('treeGenerator works without .project', function() {
       var TheAddon = Addon.extend({
         name: 'such name',
         root: path.resolve(fixturePath, 'simple')
       });
       var addon = new TheAddon();
       expect(function() {
+        var warning;
+        console.warn = function(message) {
+          warning = message;
+        }
+
         addon.treeGenerator('foo');
+        expect(warning).to.match(/Addon: `such name` is missing addon.project/);
       }).to.not.throw();
     });
   });