Summary & Key Takeaways ​

• Adds a new dev diagnostic, ASYNC_STORE_SETTER, which throws when a store setter callback returns a Promise.
• This prevents silent data loss as store setters are synchronous transactions.
• Introduces configureClientErrors({ onError }) as a client error hook for solid-js and render/hydrate.
• The client error hook provides a production-tier seam to catch component failures not handled by createErrorBoundary.
• Uncaught errors still report to the platform's reportError, ensuring existing monitors still function.

Our Commentary ​

This is a big one for SolidJS 2.0. That ASYNC_STORE_SETTER diagnostic is a lifesaver; I've definitely seen developers (myself included) make that mistake, and having it throw in dev is just good. The client error hook is also a huge step forward for building truly resilient applications. It feels like SolidJS is really maturing its error story, which is something I always look for in a framework.