extensions/git/src/repository.ts/ResourceCommandResolver/getLeftResource
class ResourceCommandResolver:	private getLeftResource(resource: Resource): Uri | undefined {
		switch (resource.type) {
			case Status.INDEX_MODIFIED:
			case Status.INDEX_RENAMED:
			case Status.INDEX_ADDED:
				return toGitUri(resource.original, 'HEAD');

			case Status.MODIFIED:
			case Status.UNTRACKED:
				return toGitUri(resource.resourceUri, '~');

			case Status.DELETED_BY_US:
			case Status.DELETED_BY_THEM:
				return toGitUri(resource.resourceUri, '~1');
		}
		return undefined;
	}