“Composer require local package”: Working with symlinked Composer packages in PHP

When developing a PHP library/package, you most likely also have a project on disk that consumes said library. Take a WordPress plugin for example: to test it, you need a WordPress installation — both are linked but separate projects. To speed up development you can tell Composer to use the local version of the package, instead of having to copy files from folder to folder as you develop.

~

I’m assuming a folder structure like this:

bramus in ~/repos
$ tree -L 1
.
├── my-library
└── my-project

If my-project were to use the published version of my-library, you would run the following command:

bramus in ~/repos/my-project
$ composer require author/my-library

The ~/repos/my-project/composer.json would then look as follows:

{
    // …
    "require": {
        "author/my-library": "*"
    }
}

~

During development of my-library you don’t want to be editing the copy of my-library which resides inside the my-project/vendor/… folder. What you want is to edit the local version of ~/repos/my-library directly, and make my-project use that version.

To do this, Composer allows you to configure the package sources using the repositories option of its configuration. To refer to the local copy adjust ~/repos/my-project/composer.json so that it has an entry pointing to ~/repos/my-library/:

{
    // …
    "require": {
        "author/my-library": "*"
    },
    "repositories": [
        {
            "type": "path",
            "url": "../my-library"
        }
    ]
}

With this addition, re-run the composer require command, and it’ll symlink ~/repos/my-library/ into ~/repos/my-project/vendor/author/my-library/:

bramus in ~/repos/my-project
$ composer require author/my-library

- Installing author/my-library (dev)
Symlinked from ../my-library

When you now edit code inside ~/repos/my-library/, the ~/repos/my-project will also be up-to-date 🙂