fix: keep flushing new eager effects#18102
Merged
Merged
Conversation
The previous code "swallowed" new additions to the array of eager effects that happened while flushing since `eager_flush` did not clear the array before running, only afterwards. Now it clears the beforehand, causing newly added eager effects to run, too. An example where this can happen is `$state.eager` and `$effect.pending` in combination: first `$state.eager` is flushed, then due to `flushSync` the `queue_micro_task` inside `boundary.js` that flushes `$effect.pending` is triggered synchronously, adding new entries to the `eager_versions` array. If they're only cleared at the end of `eager_flush`, new entries are swallowed. Related to #18095 (but not fixing it yet)
🦋 Changeset detectedLatest commit: ec43e4b The changes in this PR will be included in the next version bump. This PR includes changesets to release 1 package
Not sure what this means? Click here to learn what changesets are. Click here if you're a maintainer who wants to add another changeset to this PR |
Contributor
|
Rich-Harris
approved these changes
Apr 12, 2026
Rich-Harris
left a comment
Member
There was a problem hiding this comment.
needs changeset but otherwise LGTM
Merged
dummdidumm
pushed a commit
that referenced
this pull request
Apr 14, 2026
This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## svelte@5.55.4 ### Patch Changes - fix: never mark a child effect root as inert ([#18111](#18111)) - fix: reset context after waiting on blockers of `@const` expressions ([#18100](#18100)) - fix: keep flushing new eager effects ([#18102](#18102)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
The previous code "swallowed" new additions to the array of eager effects that happened while flushing since
eager_flushdid not clear the array before running, only afterwards. Now it clears the beforehand, causing newly added eager effects to run, too.An example where this can happen is
$state.eagerand$effect.pendingin combination: first$state.eageris flushed, then due toflushSyncthequeue_micro_taskinsideboundary.jsthat flushes$effect.pendingis triggered synchronously, adding new entries to theeager_versionsarray. If they're only cleared at the end ofeager_flush, new entries are swallowed.Related to #18095 (but not fixing it yet)