NSTableViewDiffableDataSource causes a strong retain cycle

Number:rdar://FB8959397 Date Originated:2021 Jan 2
Status:Open Resolved:
Product:AppKit Product Version:macOS 11.1 (20C69)
Classification: Reproducible:Yes
This minimal code causes a retain cycle, even when the `tableView` and `dataSource` variables go out of scope

let tableView = NSTableView()
let dataSource = NSTableViewDiffableDataSource<String, String>(
	tableView: tableView) { (tableView, column, i, model) -> NSView in
	fatalError(“Stub for compilation, this closure will never be called”)

It appears that `NSTableViewDiffableDataSource` captures its `wrapper` field (of type NSTableViewDiffableDataSourceWrapper) strongly, which in turn captures its `dataSource` field strongly.

See the attached project for a simple demo.


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