ButtonBar - add support to set the context for the widget

[lszomoru]

• This pull request reverts the changes to action.ts made in Pass metadata to agent session commands #291554 as those did not feel right
• Added support to set the context for the ButtonBar widget matching the implementation of the ActionBar
• Adopted the context for the working set ButtonBar so that we can pass session metadata to the actions

[Copilot]

Pull request overview

Adds a way to attach and forward “context” through ButtonBar/WorkbenchButtonBar so actions (and overflow context menu actions) can run with widget-specific context (e.g., chat session metadata).

Changes:

• Introduces a context property on ButtonBar and forwards it when running actions / showing overflow menus in WorkbenchButtonBar.
• Simplifies menu action argument plumbing by removing IMenuActionOptions.args and relying on arg + shouldForwardArgs.
• Updates the chat editing widget button bar to set buttonBar.context (session metadata) and forward it to actions.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/vs/workbench/contrib/chat/browser/widget/input/chatInputPart.ts	Sets up MenuWorkbenchButtonBar with shouldForwardArgs and assigns buttonBar.context to session metadata.
src/vs/platform/actions/common/actions.ts	Removes IMenuActionOptions.args and updates MenuItemAction.run to only use arg + forwarded args.
src/vs/platform/actions/browser/buttonbar.ts	Passes this.context into ActionRunner.run and into overflow context menu execution context.
src/vs/base/browser/ui/button/button.ts	Adds context getter/setter to the base ButtonBar.

[Copilot]

_context is declared but never definitely assigned. With strict TS settings this will fail strictPropertyInitialization for ButtonBar. Initialize it (e.g. to undefined) and/or widen the type to include undefined so callers can omit context safely.

Suggested change

	private _context: unknown;
	get context(): unknown {
	return this._context;
	}
	set context(context: unknown) {
	private _context: unknown | undefined = undefined;
	get context(): unknown | undefined {
	return this._context;
	}
	set context(context: unknown | undefined) {

[jrieken]

Thanks. Agree, the changes in action.ts are bad most go out asap. Tho, IMO context is an anti-pattern (which is unfortunately wide-spread) because it means actions work different when clicked (from the button/tool bar) vs when invoked via keybinding. For the latter case actions already need to be able to discover/lookup their context and that logic should also work when a button is clicked

[lszomoru]

@jrieken, closing the PR as discussed.