Docs controls not updating on args changes HMR (also present in 6.3)

[shilman]

Repro. In any args story:

1. open the story in the DocsPage tab
2. edit an arg in the story file
3. observe the story update but the ArgsTable control not update

[steven-pribilinskiy]

Also happened here with a Boolean control

[tmeasday]

@shilman so the issue is this code here:

https://github.com/storybooks/storybook/blob/84603ec40351e67a3d47ffbbd89750bba4b05872/addons/docs/src/blocks/ArgsTable.tsx#L58-L67

So the args state is set once to storyContext.args and then never set again, except via the events.

1. When you change args, the events are fired, so that works.
2. When you change story (to a different component) a whole new docs container is rendered, so a new ArgsTable is re-created, so that works.
3. When you HMR the story, there are no events or recreation, so we don't pick it up.

I'm not quite sure what the best solution is. Here are some quick thoughts:

a) We could emit an event when the implementation of a story changes (i.e. HMR), and pick that up here.
b) We could take steps to ensure the args table (or entire docs container) is recreated on HMR.
c) We could add some kind of key to the docs context that changes whenever HMR happens

[shilman]

Yowza!! I just released https://github.com/storybookjs/storybook/releases/tag/v6.4.0-beta.22 containing PR #16488 that references this issue. Upgrade today to the @next NPM tag to try it out!

npx sb upgrade --prerelease

Closing this issue. Please re-open if you think there's still more to do.