require-disposable-transfer

Require calls returning IDisposable to transfer ownership to a caller, field, or disposable collection.

Why

Functions that return IDisposable hand cleanup responsibility to the caller. Ignoring the returned value usually means the cleanup path has been lost.

Rule details

This rule checks factory-like call expressions such as create*, make*, build*, and new* whose return type is compatible with IDisposable or IObservableDisposable when TypeScript type information is available. It also recognizes the known Lumino factories DisposableSet.from(...) and ObservableDisposableSet.from(...). It ignores disposable values created directly inside a typed Jupyter plugin activate function, where services commonly live for the application lifetime.

It accepts common ownership patterns:

• Adding the result to a typed DisposableSet or a conventionally named disposable collection such as this._disposables.add(...)
• Passing the result as a direct array item to DisposableSet.from(...) or ObservableDisposableSet.from(...)
• Returning the result
• Assigning it to an object field
• Storing it in a class-field collection with this._items.set(...)
• Calling .dispose() immediately
• Storing it in a variable that is later added, returned, assigned to a field, or disposed
• Passing it to a configured ownership helper function or default ownership sink such as add, addCell, addItem, addMenu, addWidget, insertWidget, or registerStatusItem
• Passing it through a known owned constructor options object, such as new MainAreaWidget({ content }) or new Dialog({ body })

By default, the rule does not report common borrowed-reference, fluent-initializer, or registration-return calls such as get, find, getCurrent, contextForWidget, insertCell, insertTab, initializeState, contextMenuWidget, add, addCommand, addFileType, addItem, addWidgetExtension, addToolbarButtonClass, addCommandToolbarButtonClass, addTab, delete, open, openInspector, openOrReveal, findWidget, _findWidgetByID, widgetAt, widgetRenderer, pop, shift, registerItem, registerStatusItem, addKeyBinding, addGroup, register, set, transform, and add*Factory.

Incorrect

createDisposable();

const disposable = createDisposable();
console.log(disposable);

Correct

this._disposables.add(createDisposable());

const disposable = createDisposable();
disposable.dispose();

return createDisposable();

const disposables = DisposableSet.from([createDisposable()]);
disposables.dispose();

Options

ownershipFunctionNames

Function or method names that take ownership of disposable arguments. The default list is add, addCell, addFactory, addItem, addModelFactory, addSibling, addMenu, addWidget, addWidgetFactory, insertItem, insertWidget, and registerStatusItem. If provided, this list replaces the default. Set this option to [] to require stricter typed ownership checks.

ignoredReturnFunctionNames

Function or method names whose disposable return value should be treated as borrowed or owned by a registration/session API. If provided, this list replaces the default and opts into stricter return checking for non-factory calls. Set this option to [] to report ignored registration return values.

{
  "jupyter/require-disposable-transfer": [
    "warn",
    {
      "ownershipFunctionNames": ["ownDisposable", "registerDisposable"],
      "ignoredReturnFunctionNames": ["addCommand", "get", "find"]
    }
  ]
}