fix[compiler playground]: Set source as the pre-change state in HIR diff

[shun-shobon]

Summary

I have fixed an issue where the display of the HIR diff in the React Compiler Playground was incorrect. The HIR diff is supposed to show the pre-change state as the source, but currently, it is showing EnvironmentConfig as the pre-change state. This PR corrects this by setting the pre-change state to source instead of EnvironmentConfig.

How did you test this change?

before:

after:

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Name	Status	Preview	Comments	Updated (UTC)
react-compiler-playground	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jun 20, 2024 4:45am

[react-sizebot]

Comparing: 6b4646c...df682f8

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.js	=	6.66 kB	6.66 kB	=	1.82 kB	1.82 kB
oss-stable/react-dom/cjs/react-dom-client.production.js	=	497.93 kB	497.93 kB	=	89.26 kB	89.26 kB
oss-experimental/react-dom/cjs/react-dom.production.js	=	6.67 kB	6.67 kB	=	1.83 kB	1.83 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js	=	502.75 kB	502.75 kB	=	89.96 kB	89.96 kB
facebook-www/ReactDOM-prod.classic.js	=	597.17 kB	597.17 kB	=	105.33 kB	105.33 kB
facebook-www/ReactDOM-prod.modern.js	=	571.52 kB	571.52 kB	=	101.27 kB	101.27 kB
test_utils/ReactAllWarnings.js	Deleted	62.88 kB	0.00 kB	Deleted	15.69 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	62.88 kB	0.00 kB	Deleted	15.69 kB	0.00 kB

Generated by 🚫 dangerJS against df682f8

[josephsavona]

Thanks for the PR! I’ve never actually used the diff mode for the HIR panel, because there is nothing to diff against. Would you mind changing to just make the diff source empty for this panel? Diffing against the source doesn’t make sense since they’re such different representations.

[shun-shobon]

Thank you for reviewing the PR! I have updated it so that the HIR diff is no longer displayed.

screenshot

[poteto]

Looks good, thank you!