fix(signals): don't route an already-caught error past its Errored through a Loading

[brenelz]

Summary

In the Errored > Loading > Errored > content composition, a sync error thrown by the content was routed past the inner Errored to the boundary above the Loading — the outer fallback replaced the whole subtree, and with no outer boundary the error escaped entirely and (new in beta.16) permanently halted reactivity. This broke the React-style Suspense > ErrorBoundary > content nesting that TanStack Router mirrors; it worked on 2.0.0-beta.15 and regressed in beta.16 with the #2809 boundary notify-through work.

It reproduced both when the content threw during the same flush the boundaries mounted (e.g. navigating to a route that renders already-errored) and when it threw reactively after a healthy commit.

Root cause

When the inner Errored catches, CollectionQueue#notify consumes the ERROR dimension from the notification mask (type) and forwards only the PENDING remainder up the queue chain. But the Loading queue's notify-through remap keyed off the node's raw status flags instead of the mask — it saw "this node has an error", remapped the PENDING-only remainder back into an ERROR notification, and forwarded the already-caught error past its handler.

Fix

The remap now additionally requires the ERROR dimension to still be live in the mask (type & STATUS_ERROR), i.e. it only fires while the error is still unhandled — which is exactly the Errored > Loading > erroring content case the rule was written for (#2821).

Testing

• Three new regression tests in createErrorBoundary.test.ts pinning the composition: throw in the mounting flush, reactive throw after a healthy commit, and an async rejection — all must catch at the inner boundary.
• Full solid-signals, solid, and solid-web (client/SSR/hydration) suites pass, including the 2.0.0-beta.15 | Error thrown by async read in <Loading> is not captured by a wrapping <Errored> #2821 errored-async-nesting pins that motivated the notify-through rule.
• Verified against the published packages that @solidjs/signals 2.0.0-beta.15 catches at the inner boundary and 2.0.0-beta.16 routes to the outer boundary in the same scenarios.

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: b3c1c16

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 9 packages

Name	Type
@solidjs/signals	Patch
test-integration	Patch
solid-js	Patch
babel-preset-solid	Patch
@solidjs/web	Patch
@solidjs/html	Patch
@solidjs/h	Patch
@solidjs/universal	Patch
@solidjs/element	Patch

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[codspeed-hq]

Merging this PR will degrade performance by 55.9%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 1 regressed benchmark
✅ 119 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	merge	73.6 µs	166.8 µs	-55.9%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing brenelz:fix/loading-errored-composition-escape (b3c1c16) with next (ef4d53e)}