Updating core with Composer doesn't work

Question

I am on D 8.3.0-rc2 and want to update to D 8.3.0 stable. Composer is my only option (requirement of address module). Composer core update doesn't bring me beyond 8.3-0-rc2, not even forcing it. Running drush composer require "drupal/core:^8.3@stable" gives me the following output:

./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Nothing to install or update

The content of composer.json is the following.

{

"name": "drupal/drupal",
"description": "Drupal is an open source content management platform powering millions of websites and applications.",
"type": "project",
"license": "GPL-2.0+",
"require": {
    "composer/installers": "^1.0.21",
    "drupal/core": "^8.3@stable",
    "wikimedia/composer-merge-plugin": "~1.3",
    "drupal/address": "~1.0",
    "drush/drush": "^8.1"
},
"replace": {
},
"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."
    ],
    "merge-plugin": {
        "include": [
            "core/composer.json"
        ],
        "recurse": false,
        "replace": false,
        "merge-extra": false
    }
},
"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"
},
"repositories": {
    "drupal": {
        "type": "composer",
        "url": "https://packages.drupal.org/8"
    }
}
}

I read about deleting vendor and composer.lock, but I don't understand why this would work.

Answer 1

Instead of trying to update Drupal directly with Composer, instead try starting with drupal-composer/drupal-project as a starting point. This project definitely works with Drupal 8.3.0.

Set up a new project with drupal-composer/drupal-project, and use composer require to add any modules you need. Once your code is the same in the new project as the old, you should be able to just copy the database over (or just point to your existing database with settings.php) and run updatedb.

Answer 2

You already have the right version in your composer.json. Then it's just composer install (in your case it's drush composer install).

If that not works, delete your lock file and/or the vendor folder prior to calling composer install (or drush composer install).

And I guess composer update drupal/core (in your case drush composer update drupal/core) might work as well (since the version in your lock file or in the vendor folder is different from that in your composer.jon).