How to await a build task in a VS Code extension?

Question

let result = await vscode.commands.executeCommand('workbench.action.tasks.build');

resolves immediately.

How can I await a build task with VS Code API?

Answer 1

I figured it out! Tasks cannot be awaited from vscode.tasks.executeTask, but we can await vscode.tasks.onDidEndTask and check if ended task is our task.

async function executeBuildTask(task: vscode.Task) {
    const execution = await vscode.tasks.executeTask(task);

    return new Promise<void>(resolve => {
        let disposable = vscode.tasks.onDidEndTask(e => {
            if (e.execution.task.group === vscode.TaskGroup.Build) {
                disposable.dispose();
                resolve();
            }
        });
    });
}

async function getBuildTasks() {
    return new Promise<vscode.Task[]>(resolve => {
        vscode.tasks.fetchTasks().then((tasks) => {
            resolve(tasks.filter((task) => task.group === vscode.TaskGroup.Build));
        });
    });
}

export function activate(context: vscode.ExtensionContext) {
    context.subscriptions.push(vscode.commands.registerCommand('extension.helloWorld', async () => {
        const buildTasks = await getBuildTasks();
        await executeBuildTask(buildTasks[0]);
    }));
}

Note that currently there is a bug #96643, which prevents us from doing a comparison of vscode.Task objects: if (e.execution.task === execution.task) { ... }