fix: ensure unowned deriveds correctly get re-linked to the graph

[trueadm]

Fixes #14846. This ensures that we properly attach unowned deriveds to their dependencies. Previously, we might only attach one of the dependencies if that dependency was also a mismatched version – which meant we skipped all the other dependencies.

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Latest commit: 3f8c7dd

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

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[github-actions]

Playground

pnpm add https://pkg.pr.new/svelte@14855

[webJose]

BTW, the repro code in #14846 works in this PR's playground. Great job.

[gyzerok]

I've tried this fix in our codebase and it definitely improves memory profile. Some previously leakish stuff got fixed. Great job!

If possible would be great if it can be released in a version before unsafe branch, since the latter one seems a bit scary for us. Would be great if we could update to this fix and then take our time to check everything in the unsafe branch works correctly for us.

[baseballyama]

I’m not familiar with the Svelte 5 codebase, but this looks like the correct fix. It also worked fine in the REPL.