list: [hotfix] drop runtime.SetFinalizer This commit removes the use of runtime.SetFinalizer from list.Manager. I added it in order to try to ensure that the goroutine it spawns was always cleaned up, but I didn't realize that doing so would break the garbage collector's ability to GC the manager if any of the manager's hook functions managed to create an import cycle (this is very easy to do, as it's natural to provide methods on a type containing the manager as hooks). https://pkg.go.dev/runtime#SetFinalizer says: If a cyclic structure includes a block with a finalizer, that cycle is not guaranteed to be garbage collected and the finalizer is not guaranteed to run, because there is no ordering that respects the dependencies. This means we can't safely automate the destruction of that goroutine, and must rely upon users to properly invoke Shutdown(). Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>
1 files changed, 0 insertions(+), 7 deletions(-) M list/manager.go
M list/manager.go => list/manager.go +0 -7
@@ 3,7 3,6 @@ package list import ( "fmt" "math" "runtime" "sync" "gioui.org/layout" @@ 156,12 155,6 @@ func NewManager(maxSize int, hooks Hooks) *Manager { rm.requests, rm.viewports, rm.stateUpdates = asyncProcess(maxSize, hooks) // Ensure that the asynchronous processing goroutine is shut down when // the manager is garbage collected. runtime.SetFinalizer(rm, func(m *Manager) { m.Shutdown() }) return rm }