extensions/github/src/pushErrorHandler.ts/handlePushError
async function handlePushError(repository: Repository, remote: Remote, refspec: string, owner: string, repo: string): Promise<void> {
	const yes = localize('create a fork', "Create Fork");
	const no = localize('no', "No");

	const answer = await window.showInformationMessage(localize('fork', "You don't have permissions to push to '{0}/{1}' on GitHub. Would you like to create a fork and push to it instead?", owner, repo), yes, no);
	if (answer === no) {
		return;
	}

	const match = /^([^:]*):([^:]*)$/.exec(refspec);
	const localName = match ? match[1] : refspec;
	let remoteName = match ? match[2] : refspec;

	const [octokit, ghRepository] = await window.withProgress({ location: ProgressLocation.Notification, cancellable: false, title: localize('create fork', 'Create GitHub fork') }, async progress => {
		progress.report({ message: localize('forking', "Forking '{0}/{1}'...", owner, repo), increment: 33 });

		const octokit = await getOctokit();

		type CreateForkResponseData = Awaited<ReturnType<typeof octokit.repos.createFork>>['data'];

		// Issue: what if the repo already exists?
		let ghRepository: CreateForkResponseData;
		try {
			if (isInCodespaces()) {
				// Call into the codespaces extension to fork the repository
				const resp = await commands.executeCommand<{ repository: CreateForkResponseData, ref: string }>('github.codespaces.forkRepository');
				if (!resp) {
					throw new Error('Unable to fork respository');
				}

				ghRepository = resp.repository;

				if (resp.ref) {
					let ref = resp.ref;
					if (ref.startsWith('refs/heads/')) {
						ref = ref.substr(11);
					}

					remoteName = ref;
				}
			} else {
				const resp = await octokit.repos.createFork({ owner, repo });
				ghRepository = resp.data;
			}
		} catch (ex) {
			console.error(ex);
			throw ex;
		}

		progress.report({ message: localize('forking_pushing', "Pushing changes..."), increment: 33 });

		// Issue: what if there's already an `upstream` repo?
		await repository.renameRemote(remote.name, 'upstream');

		// Issue: what if there's already another `origin` repo?
		await repository.addRemote('origin', ghRepository.clone_url);

		try {
			await repository.fetch('origin', remoteName);
			await repository.setBranchUpstream(localName, `origin/${remoteName}`);
		} catch {
			// noop
		}

		await repository.push('origin', localName, true);

		return [octokit, ghRepository];
	});

	// yield
	(async () => {
		const openOnGitHub = localize('openingithub', "Open on GitHub");
		const createPR = localize('createpr', "Create PR");
		const action = await window.showInformationMessage(localize('forking_done', "The fork '{0}' was successfully created on GitHub.", ghRepository.full_name), openOnGitHub, createPR);

		if (action === openOnGitHub) {
			await commands.executeCommand('vscode.open', Uri.parse(ghRepository.html_url));
		} else if (action === createPR) {
			const pr = await window.withProgress({ location: ProgressLocation.Notification, cancellable: false, title: localize('createghpr', "Creating GitHub Pull Request...") }, async _ => {
				let title = `Update ${remoteName}`;
				const head = repository.state.HEAD?.name;

				if (head) {
					const commit = await repository.getCommit(head);
					title = commit.message.replace(/\n.*$/m, '');
				}

				const res = await octokit.pulls.create({
					owner,
					repo,
					title,
					head: `${ghRepository.owner.login}:${remoteName}`,
					base: remoteName
				});

				await repository.setConfig(`branch.${localName}.remote`, 'upstream');
				await repository.setConfig(`branch.${localName}.merge`, `refs/heads/${remoteName}`);
				await repository.setConfig(`branch.${localName}.github-pr-owner-number`, `${owner}#${repo}#${pr.number}`);

				return res.data;
			});

			const openPR = localize('openpr', "Open PR");
			const action = await window.showInformationMessage(localize('donepr', "The PR '{0}/{1}#{2}' was successfully created on GitHub.", owner, repo, pr.number), openPR);

			if (action === openPR) {
				await commands.executeCommand('vscode.open', Uri.parse(pr.html_url));
			}
		}
	})();
}