Unreliable focus change when closing windows. Focus race condition with macOS

[nikitabobko]

When the window is closed, AeroSpace receives two events from macOS:

• The window is destroyed
• The focused window is changed

The events system is unreliable in macOS. The events might come in whatever order, or sometimes the events might not be even delivered 🤷

AeroSpace logic relies neither on the nature of the events nor on their order. AeroSpace only uses events as a signal to "re-evaluate the world" (check if windows no longer exist, check if new windows are appeared, re-layout the windows)

And here comes the problem, whenever AeroSpace detects that the window is destroyed, AeroSpace issues a focus request to focus the previously focused window on the workspace of the destroyed window. We do so to keep the focused workspace focused (Pointer in the code: MacWindow.swift:garbageCollect). Unfortunately, AeroSpace plays a "race condition" game with the macOS that tries to focus next window of the app.

It leads to the following user facing issue: AeroSpace may lose the "race condition" #854 #571

What is the proposed solution to fix the problem? I don't have one. I don't know. Until it's clear how to fix the issue, the issue exists for the documentation purposes.

Also read the thread: #571