Controls reset when hot reloading

[florian-milky]

Describe the bug
When developing a component using a story and controls, everytime the code is saved, the story reloads with default control values.

To Reproduce
Steps to reproduce the behavior:

1. create a story with controls
2. run storybook locally
3. change some control values
4. update your component

Expected behavior
story should hot reload with same controls

Screenshots
N/A

Code snippets
N/A

System
Environment Info:

System:
OS: macOS 10.15.6
CPU: (8) x64 Intel(R) Core(TM) i5-8279U CPU @ 2.40GHz
Binaries:
Node: 14.13.1 - ~/.nvm/versions/node/v14.13.1/bin/node
npm: 6.14.8 - ~/.nvm/versions/node/v14.13.1/bin/npm
Browsers:
Chrome: 87.0.4280.88
Safari: 13.1.2
npmPackages:
@storybook/addon-actions: ^6.1.9 => 6.1.9
@storybook/addon-essentials: ^6.1.9 => 6.1.9
@storybook/addon-knobs: ^6.1.9 => 6.1.9
@storybook/addon-links: ^6.1.9 => 6.1.9
@storybook/addons: ^6.1.9 => 6.1.9
@storybook/react: ^6.1.9 => 6.1.9

Additional context
Add any other context about the problem here.

[tmeasday]

Hi @florian-milky -- can you tell if your app is HMR (hot module reloading / fast refreshing without reloading the browser tab) or not?

I would be surprised if the args were being reset on HMR (in which case a reproduction would be useful). OTOH if your SB is reloading when you edit a component, you might want to investigate why, although I tend to think args shouldn't reset then either (we already store globals in session storage, we should store args there too I think).

[florian-milky]

Thanks @tmeasday.
Yes I am using HMR. I will investigate if something is refreshing at a too high level, and I'll report back.

[florian-milky]

I had to enable fast refresh.
Didn't think it wouldn't be added by default :)

---

• You can set a FAST_REFRESH environment variable in your .env file:

FAST_REFRESH=true

• Or you can set the following properties in your .storybook/main.js files:

module.exports = {
  reactOptions: {
    fastRefresh: true,
  }
};

[tmeasday]

I still think we should retain control values if HMR isn't working 👍

[tmeasday]

This will be fixed by #13803 and as such is probably subsumed by #12291