v3.4.4

This is the thirty-fourth release in the Cats Effect 3.x lineage. It is fully binary compatible with every 3.x release, and fully source-compatible with every 3.4.x release. Note that source compatibility has been broken with 3.3.x in some minor areas. Since those changes require active choice on the part of users to decide the best adjusted usage for their specific scenario, we have chosen to not provide scalafixes which automatically patch the affected call sites.

This release fixes a memory leak in Deferred. The memory leak in question is relatively small, but can accumulate over a long period of time in certain common applications. Additionally, this leak regresses GC performance slightly for almost all Cats Effect applications. For this reason, it is highly recommended that users upgrade to this release as soon as possible if currently using version 3.4.3.

User-Facing Pull Requests

• #3336 – Update scala-js-macrotask-executor to 1.1.1 (@armanbilge)
• #3334 – Fix compile using CallbackStack#clear method (@armanbilge)
• #3324 – Specialize CallbackStack on JS (@armanbilge)
• #3333 – Avoid leaks in IODeferred (@durban)
• #3307 – Fix propagation of ExitCase in Resource#{both,combineK} (@armanbilge)

Thank you so very much!