Add revolt/event-loop dependency to core

+1 to this. Having looked at (but not actually tried to use) the react/amp projects I'm not sure how useful those will be for us, but revolt is a layer below both of those, and would save us copying the fiber foreach loops around as we slowly introduce async support into more places.

Taking the RM review tag off, but leaving the FM review tag on so this gets a +1 from another core committer who's not me.

The Needs Review Queue Bot → tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

Consult the Drupal Contributor Guide → to find step-by-step guides for working with issues.

Rebased

Do we have a list or meta somewhere of places we want to use async for?

Yes, there's 2 issues blocked on it, listed in "Referenced by"

📌 [PP-1] Ensure asynchronous tasks that run beyond the length of a request have the chance to complete before process exit Active
📌 [PP-2] Migrate BigPipe and Renderer fiber implementation to use Revolt Event Loop Postponed

🌱 [meta] Use Fibers for concurrency in core Active is the meta.

Thanks, removing tag

Last 2 remaining tasks have been resolved (updated IS with comments they were)

Dependency evaluation appears complete and has gotten multiple +1s.

Going out on a limb and marking.

The Needs Review Queue Bot → tested this issue. It no longer applies to Drupal core. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

Consult the Drupal Contributor Guide → to find step-by-step guides for working with issues.

Rebased.

Appears to need another rebase, will keep an eye out to get remarked quickly

Rebased again.

Rebase appears green!

I've split out 📌 Use revolt to prewarm caches during lock waits Active from 📌 Add a cache prewarm API and use it to distribute cache rebuids after cache clears / during stampedes Needs work to simplify the dependencies for that issue.

Added the various issues waiting on this one to the issue summary.

I worked on the initial Fibers implementation for core, however I was not familiar with Revolt at that time (to be fair it was only a few months old then - spun out of two older async projects as part of those projects also adopting Fibers). And while some of the concepts are new for Drupal, having them codified by a library that's also used by both amphp and react PHP should hopefully make them easier for people to pick up than manually re-implementing some of them with raw Fibers ourselves.

Committed/pushed to 11.x, thanks!

catch → closed merge request !6865

Why is this in the the root composer.json - it doesn't belong there. It should only be in core/composer.json.

Fixed #24 in a quick follow-up.

Tagging due to changes in the Core dependency release cycles and evaluation criteria → policy.

Automatically closed - issue fixed for 2 weeks with no activity.