Updating from Laravel 5.8 to 6.0 fails due to dependencies

Question

I'm trying to update from 5.8 to any version 6 Laravel. I've updated the PHP code, but the composer update is problematic for me. I've tried composer update, composer update --with-dependencies, composer install.

Composer isn't something I work with often. Any help is very appreciate! How do I decipher the composer error message to an actionable task? Is there a command that will install the dependencies for Laravel 6?

The error message after composer update:

 - Conclusion: don't install laravel/framework v6.0.0
    - arcanedev/support 4.5.0 requires illuminate/support ~5.8.0 -> satisfiable by laravel/framework[v5.8.38], illuminate/support[5.8.x-dev, v5.8.0, v5.8.11, v5.8.12, v5.8.14, v5.8.15, v5.8.17, v5.8.18, v5.8.19, v5.8.2, v5.8.20, v5.8.22, v5.8.24, v5.8.27, v5.8.28, v5.8.29, v5.8.3, v5.8.30, v5.8.31, v5.8.32, v5.8.33, v5.8.34, v5.8.35, v5.8.36, v5.8.4, v5.8.8, v5.8.9].
    - arcanedev/support 4.5.0 requires illuminate/support ~5.8.0 -> satisfiable by laravel/framework[v5.8.38], illuminate/support[5.8.x-dev, v5.8.0, v5.8.11, v5.8.12, v5.8.14, v5.8.15, v5.8.17, v5.8.18, v5.8.19, v5.8.2, v5.8.20, v5.8.22, v5.8.24, v5.8.27, v5.8.28, v5.8.29, v5.8.3, v5.8.30, v5.8.31, v5.8.32, v5.8.33, v5.8.34, v5.8.35, v5.8.36, v5.8.4, v5.8.8, v5.8.9].
    - Can only install one of: laravel/framework[6.x-dev, v5.8.38].
    - don't install illuminate/support 5.8.x-dev|don't install laravel/framework 6.x-dev


 - don't install illuminate/support v5.8.9|don't install laravel/framework 6.x-dev
    - Installation request for laravel/framework ^6.0 -> satisfiable by laravel/framework[6.x-dev, v6.0.0, v6.0.1, v6.0.2, v6.0.3, v6.0.4, v6.1.0, v6.10.0, v6.10.1, v6.11.0, v6.12.0, v6.13.0, v6.13.1, v6.14.0, v6.15.0, v6.15.1, v6.16.0, v6.17.0, v6.17.1, v6.18.0, v6.18.1, v6.18.10, v6.18.11, v6.18.12, v6.18.13, v6.18.14, v6.18.15, v6.18.16, v6.18.17, v6.18.18, v6.18.19, v6.18.2, v6.18.20, v6.18.21, v6.18.22, v6.18.23, v6.18.24, v6.18.25, v6.18.26, v6.18.27, v6.18.28, v6.18.29, v6.18.3, v6.18.30, v6.18.31, v6.18.4, v6.18.5, v6.18.6, v6.18.7, v6.18.8, v6.18.9, v6.2.0, v6.3.0, v6.4.0, v6.4.1, v6.5.0, v6.5.1, v6.5.2, v6.6.0, v6.6.1, v6.6.2, v6.7.0, v6.8.0, v6.9.0].
    - Installation request for arcanedev/support ~4.5 -> satisfiable by arcanedev/support[4.5.0].

The composer.json

{
    "name": "laravel/laravel",
    "type": "project",
    "description": "The Laravel Framework.",
    "keywords": [
        "framework",
        "laravel"
    ],
    "license": "MIT",
    "require": {
        "php": "^7.2",
        "laravel/framework": "^6.0",
        "fideloper/proxy": "^4.0",
        "guzzlehttp/guzzle": "^6.3",
        "illuminate/support": "~5.8.0|^6.0",
        "intervention/image": "^2.4",
        "laravel/tinker": "^1.0",
        "spatie/laravel-permission": "^3.0"
    },
    "require-dev": {
        "barryvdh/laravel-ide-helper": "^2.6",
        "beyondcode/laravel-dump-server": "^1.0",
        "filp/whoops": "^2.0",
        "fzaninotto/faker": "^1.4",
        "mockery/mockery": "^1.0",
        "nunomaduro/collision": "^2.0",
        "phpunit/phpunit": "^7.0",
        "barryvdh/laravel-debugbar": "^3.2",
        "arcanedev/log-viewer": "^4.7",
        "arcanedev/support": "~4.5"
    },
    "config": {
        "optimize-autoloader": true,
        "preferred-install": "dist",
        "sort-packages": true
    },
    "extra": {
        "laravel": {
            "dont-discover": []
        }
    },
    "autoload": {
        "psr-4": {
            "App\\": "app/"
        },
        "classmap": [
            "database/seeds",
            "database/factories"
        ]
    },
    "autoload-dev": {
        "psr-4": {
            "Tests\\": "tests/"
        }
    },
    "minimum-stability": "dev",
    "prefer-stable": true,
    "scripts": {
        "post-autoload-dump": [
            "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
            "@php artisan package:discover --ansi"
        ],
        "post-root-package-install": [
            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "@php artisan key:generate --ansi"
        ]
    }
}

Answer 1

Just have a look at the error message you've shared: your configuration requires arcanedev/support with the version constraint ~4.5. By peeking into the version list of that package, you can see that there is only one version that can be used, which is 4.5.0, and this package requires illuminate/support with the version constraint ~5.8.0. Obviously, this excludes any later versions of Laravel.

By also updating arcanedev/support to some later version (^5.0 should be fine), you are able to update Laravel. Packagist can help you to inspect the constraints for different versions of that package.