README

Serves package testing purposes only... obviously.

💿 composer require foobar/foobar8

Usage

When migrating from a package to another, it may be useful to know that composer schema (i.e. composer.json) may contain replace property.

The schema of this package is (abridged):

{
  "name": "foobar/foobar8",
  "require": {
    "php": "^8"
  },
  "replace": {
    "foobar/foobar7": "*"
  }
}

Where replace indicates that foobar/foobar8 completely replaces foobar/foobar7, allowing Composer to consider foobar/foobar8 as a drop-in replacement for foobar/foobar7.

Prop replace creates an implicit conflict rule, and is also more useful than provide, which serves different purpose (to implement virtual interfaces).

Read the Composer schema docs here: Composer replace.

Migration

Prerequisites (or current state):

• project running on PHP 7
• foobar/foobar7 installed (i.e. required by the project)

Migration:

1. switch to PHP 8
2. composer require foobar/foobar8
3. (optional) remove foobar/foobar7 requirement

This will satisfy all the other libraries that depend on foobar/foobar7, too, not just the project itself.

One should end up with something like this:

{
  "type": "project",
  "require": {
    "php": "^8",
    "foobar/foobar7": "^1",
    "foobar/foobar8": "^1"
  }
}

Useful when reimplementing older libraries or providing backport versions for older architectures.

It may be useful in other scenarios too, when reimplementing third party libraries.
An example would be a library that is slow to be maintained, but a serious flaw is found. One may source and distribute the patch himself and only replace a certain version. Once the third party package is updated, it will be used again, without need for changes to the consuming project.

Note that the replacing works not only across PHP versions. One may replace any package, or even selected versions of a package.