When I yarn upgrade a package I have to restart create-react-app server

Created by: tnrich

When I run yarn upgrade package-name-xxx, I need to restart the dev server in order to see those changes.

Here are steps to reproduce. (Note the following example uses a an npm package I made, https://github.com/tnrich/semver-console , that just console logs its semver number when required.)

In terminal tab #1:

(using latest version of create-react-app@1.3.3)
create-react-app yarn-upgrade-test
cd yarn-upgrade-test/
yarn start

In terminal tab #2:

yarn add semver-console@0

At the top of yarn-upgrade-test/src/App.js add:

import "semver-console";

in the browser console you'll now see:

SEMVER: 0.0.0

In terminal tab #2 run:

yarn upgrade semver-console@1

in the browser console you'll still see:

SEMVER: 0.0.0

instead of the expected

SEMVER: 1.0.0

Note: The bulk of this issue was already in a comment in https://github.com/facebookincubator/create-react-app/issues/2606

This is quite a pain point for us because we use a lot of linked npm packages when developing our app and the start up time is quite slow for create-react-app.

Any help getting this resolved would be greatly appreciated. Thanks!