Packagist.org is slow in some countries, so we always use mirrors.

But mirrors changes composer.lock, such as:

        {
            "name": "laravel/framework",
            "version": "v6.3.0",
            "source": {
                "type": "git",
                "url": "https://github.com/laravel/framework.git",
                "reference": "80914c430fb5e49f492812d704ba6aeec03d80a2"
            },
            "dist": {
                "type": "zip",
                "url": "https://api.github.com/repos/laravel/framework/zipball/80914c430fb5e49f492812d704ba6aeec03d80a2",
                "reference": "80914c430fb5e49f492812d704ba6aeec03d80a2",
                "shasum": "",
                "mirrors": [
                    {
                        "url": "https://mirrors.aliyun.com/composer/dists/%package%/%reference%.%type%",
                        "preferred": true
                    }
                ]
            }
        }

If we submit this to Git, composer will run slower from other countries, such as CI(circleci.com, travis-ci.com) and other developers developers around the world.

So we need to remove mirrors in composer.lock before submit. I have wrote remove-composer-mirrors.php to do this, just run:

php -i remove-composer-mirrors.php