When I run composer gocomposer I get [ErrorException] Undefined index: namespace

[kevincyan]

I am using composer 1.8.6 on mac catalina with php 7.1.3

My composer file at the time of the error is:

{ "name": "drupal/drupal", "description": "Drupal is an open source content management platform powering millions of websites and applications.", "type": "project", "license": "GPL-2.0-or-later", "require": { "composer/installers": "^1.0.24", "wikimedia/composer-merge-plugin": "^1.4", "drush/drush": "^10.1" },

"replace": {
    "drupal/core": "^8.7"
},
"minimum-stability": "dev",
"prefer-stable": true,
"config": {
    "preferred-install": "dist",
    "autoloader-suffix": "Drupal8"
},
"extra": {
    "_readme": [
        "By default Drupal loads the autoloader from ./vendor/autoload.php.",
        "To change the autoloader you can edit ./autoload.php.",
        "This file specifies the packages.drupal.org repository.",
        "You can read more about this composer repository at:",
        "https://www.drupal.org/node/2718229"
    ],
    "merge-plugin": {
        "include": [
            "core/composer.json"
        ],
        "recurse": true,
        "replace": false,
        "merge-extra": false
    },
    "installer-paths": {
        "core": ["type:drupal-core"],
        "modules/contrib/{$name}": ["type:drupal-module"],
        "profiles/contrib/{$name}": ["type:drupal-profile"],
        "themes/contrib/{$name}": ["type:drupal-theme"],
        "drush/contrib/{$name}": ["type:drupal-drush"],
        "modules/custom/{$name}": ["type:drupal-custom-module"],
        "themes/custom/{$name}": ["type:drupal-custom-theme"]
    }
},
"autoload": {
    "psr-4": {
        "Drupal\\Core\\Composer\\": "core/lib/Drupal/Core/Composer"
    }
},
"scripts": {
    "pre-autoload-dump": "Drupal\\Core\\Composer\\Composer::preAutoloadDump",
    "post-autoload-dump": "Drupal\\Core\\Composer\\Composer::ensureHtaccess",
    "post-package-install": "Drupal\\Core\\Composer\\Composer::vendorTestCodeCleanup",
    "post-package-update": "Drupal\\Core\\Composer\\Composer::vendorTestCodeCleanup",
    "drupal-phpunit-upgrade-check": "Drupal\\Core\\Composer\\Composer::upgradePHPUnit",
    "drupal-phpunit-upgrade": "@composer update phpunit/phpunit phpspec/prophecy symfony/yaml --with-dependencies --no-progress",
    "phpcs": "phpcs --standard=core/phpcs.xml.dist --runtime-set installed_paths $($COMPOSER_BINARY config vendor-dir)/drupal/coder/coder_sniffer --",
    "phpcbf": "phpcbf --standard=core/phpcs.xml.dist --runtime-set installed_paths $($COMPOSER_BINARY config vendor-dir)/drupal/coder/coder_sniffer --"
},
"repositories": [
    {
        "type": "composer",
        "url": "https://packages.drupal.org/8"
    }
]

}

[kevincyan]

found the issue if namespace is not in the database connection settings the command will fail.

[BluAmpersand]

If your current drupal is >= 8.7.10 see my comment in issue #7, there is an issue with the regx. I explain how to fix. if you are at 8.7.9, then ignore me.