support react 19

[T4rk1n]

• Remove react 16 support.
• Add react 19 experimental support, use with:

from dash._dash_renderer import _set_react_version

_set_react_version("19.2.0")

[github-actions]

Thank you for your contribution to Dash! 🎉

This PR is exempt from requiring a linked issue due to its labels.

[AnnMarieW]

Thanks for supporting React 19 🎉

I see all the tests pass, but when I run apps setting react to 19.2.0 some components work (like dcc.Markdown and dcc.Input) but others do not, such as dcc.RangeSlider and the date picker components. The error is:

Cannot read properties of undefined (reading 'ReactCurrentOwner')

I see the same error if I set react 19 in the tests for those components.

[AnnMarieW]

I tried this again, and here's some more feedback:

The new React 19 shim seems to fix the ReactCurrentOwner error with DCC components.

I also tried a simple quick start app in a few other libraries:

• dash-ag-grid 35.2 worked fine.
• dash-daq 0.6.0 worked fine.
• dash-bootstrap-components 2.0.4 had the errors shown below. DBC v2 is based on react-bootstrap v2 which does not support React.19, so that wasn't surprising.
• dash-mantine-components 2.6.1 had the same errors as DBC. However, DMC v2 is based on Mantine v8 which is compatible with React 19, so that was a little unexpected.

---

Errors in both DMC and DBC if a component is defined in the app:

Uncaught TypeError: Cannot read properties of undefined (reading 'ReactCurrentOwner')
at Array. (dash_bootstrap_components.v2_0_4m1759328733.min.js:2:12535)
at n (dash_bootstrap_components.v2_0_4m1759328733.min.js:2:13035)
at Array. (dash_bootstrap_components.v2_0_4m1759328733.min.js:2:12343)
at n (dash_bootstrap_components.v2_0_4m1759328733.min.js:2:13035)
at dash_bootstrap_components.v2_0_4m1759328733.min.js:2:17559
at dash_bootstrap_components.v2_0_4m1759328733.min.js:2:227635
at dash_bootstrap_components.v2_0_4m1759328733.min.js:2:227674

Also, if the component is added to the layout, the app doesn't render, and there is also the following errors:

Uncaught Error: dash_bootstrap_components was not found.
at Object.resolve (registry.js:15:15)
at getProps (persistence.js:293:30)
at persistenceMods (persistence.js:404:9)
at persistence.js:437:29
at Array.forEach ()
at persistenceMods (persistence.js:435:18)
at applyPersistence (persistence.js:370:12)
at APIController.react.js:161:53
at exports.unstable_batchedUpdates (react-dom.development.js:411:14)
at storeEffect (APIController.react.js:150:10)Understand this error

installHook.js:1 An error occurred in the component.
Consider adding an error boundary to your tree to customize error handling behavior.
Visit https://react.dev/link/error-boundaries to learn more about error boundaries.
overrideMethod @ installHook.js:1Understand this warning