Track late-mounted roots in Fast Refresh

[anc95]

Summary

In doing the micro front-end sub-application encountered the problem of sub-application hot update does not work, I debugged it like this

1. use the online (test environment) main application address
2. proxy the sub-application to be debugged to localhost (localhost domain)

In order to keep the Shared React Context, our sub-application is loaded by the main application as a React component, because react-refresh is loaded only when the sub-application is executed, so the current root is not properly collected in the mountedRoots, and eventually the hot update of the application does not work.

How did you test this change?

When determining wasMounted, adjust to

const wasMounted =
            alternate.memoizedState != null &&
            alternate.memoizedState.element != null &&
            mountedRoots.has(root);

Logically, there is no breaking change here, and it solves my problem perfectly

[facebook-github-bot]

Hi @anc95!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at cla@fb.com. Thanks!

[sizebot]

Comparing: e0aa5e2...56146f8

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.min.js	=	129.68 kB	129.68 kB	=	41.46 kB	41.46 kB
oss-experimental/react-dom/cjs/react-dom.production.min.js	=	134.66 kB	134.66 kB	=	42.94 kB	42.94 kB
facebook-www/ReactDOM-prod.classic.js	=	424.11 kB	424.11 kB	=	78.18 kB	78.18 kB
facebook-www/ReactDOM-prod.modern.js	=	412.66 kB	412.66 kB	=	76.43 kB	76.43 kB
facebook-www/ReactDOMForked-prod.classic.js	=	424.11 kB	424.11 kB	=	78.18 kB	78.18 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 56146f8

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Facebook open source project. Thanks!

[gaearon]

thanks!

[benjamingr]

We just ran into this bug, super cool to see this was worked on, cheers!