Concurrent RTR in ReactHooksInspectionIntegration-test

[jackpope]

More test updates to use concurrent root in RTR

yarn test packages/react-debug-tools/src/__tests__/ReactHooksInspectionIntegration-test.js

[jackpope]

Here and L762 the assertion is updated.

It seems that in legacy root the useState setter completed (a=>A) but the useReducer setter did not (b=>B). I'm not sure why. I would expect the value to be AB here as it is now.

[rickhanlonii]

Yeah it's the batching.

It was only Ab before because they weren't batched, and if you look at the useMemo (which this snapshot is showing the state of):

React.useMemo(() => state1 + state2, [state1]);

Before, this would re-run the memo when state1 changed, which was a different render then when state 2 changed. So the memo state would only see the state1 change. With batching, both states are updated at the same time, so even though the memo still only fires on state1 changing, by that point state2 has also already changed.

[react-sizebot]

Comparing: 5cec48e...004dd8b

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	=	176.83 kB	176.83 kB	=	54.91 kB	54.91 kB
oss-experimental/react-dom/cjs/react-dom.production.min.js	=	173.26 kB	173.26 kB	=	54.04 kB	54.04 kB
facebook-www/ReactDOM-prod.classic.js	=	594.27 kB	594.27 kB	=	104.44 kB	104.44 kB
facebook-www/ReactDOM-prod.modern.js	=	577.53 kB	577.53 kB	=	101.47 kB	101.47 kB
test_utils/ReactAllWarnings.js	Deleted	66.48 kB	0.00 kB	Deleted	16.26 kB	0.00 kB

Significant size changes

Includes any change greater than 0.2%:

Expand to show

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
test_utils/ReactAllWarnings.js	Deleted	66.48 kB	0.00 kB	Deleted	16.26 kB	0.00 kB

Generated by 🚫 dangerJS against 004dd8b

[rickhanlonii]

Yeah it's the batching.

It was only Ab before because they weren't batched, and if you look at the useMemo (which this snapshot is showing the state of):

React.useMemo(() => state1 + state2, [state1]);

Before, this would re-run the memo when state1 changed, which was a different render then when state 2 changed. So the memo state would only see the state1 change. With batching, both states are updated at the same time, so even though the memo still only fires on state1 changing, by that point state2 has also already changed.