Composer package issue - composer-php

Question

I work on a project that uses composer for dependency management:
{
"require": {
"doctrine/annotations": "1.8.0",
"doctrine/dbal": "2.9.3",
"doctrine/orm": "2.7.1",
"doctrine/reflection": "1.2.0",
"giggsey/libphonenumber-for-php": "8.11.5",
"guzzlehttp/guzzle": "6.5.2",
"james-heinrich/getid3": "v1.9.19",
"php-extended/php-http-message-factory-psr17": "2.0.0",
"phpoffice/phpspreadsheet": "1.10.1",
"psr/event-dispatcher": "1.0.0",
"sabre/vobject": "4.2.2",
"sabre/xml": "2.1.3",
"spiral/roadrunner": "1.7.0",
"symfony/browser-kit": "4.4.4",
"symfony/cache": "v4.4.4",
"symfony/class-loader": "v3.4.38",
"symfony/config": "4.4.4",
"symfony/console": "4.4.4",
"symfony/css-selector": "4.4.4",
"symfony/debug": "4.4.4",
"symfony/dependency-injection": "4.4.4",
"symfony/dom-crawler": "4.4.4",
"symfony/error-handler": "4.4.4",
"symfony/event-dispatcher": "v4.4.4",
"symfony/expression-language": "4.4.4",
"symfony/filesystem": "4.4.4",
"symfony/finder": "4.4.4",
"symfony/http-foundation": "4.4.4",
"symfony/http-kernel": "4.4.4",
"symfony/mailer": "4.4.4",
"symfony/mime": "4.4.4",
"symfony/polyfill-ctype": "1.14.0",
"symfony/polyfill-intl-idn": "1.14.0",
"symfony/polyfill-mbstring": "1.14.0",
"symfony/polyfill-php72": "1.14.0",
"symfony/polyfill-php73": "1.14.0",
"symfony/process": "4.4.4",
"symfony/service-contracts": "2.0.1",
"symfony/validator": "4.4.4",
"symfony/var-dumper": "4.4.4",
"symfony/var-exporter": "4.4.4",
"symfony/yaml": "4.4.4"
}
}
I'm trying to add a new dependency to the project, namely symfony/contracts. This package replaces several other Symfony packages, among other the symfony/event-dispatcher-contracts package, which is indirectly required as a dependency in the project.
However, when running the composer require symfony/contracts command, I get an error message that I cannot figure out:
# composer require symfony/contracts:2.0.1
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- don't install symfony/event-dispatcher-contracts v1.1.7|don't install symfony/contracts v2.0.1
- don't install symfony/contracts v2.0.1|remove symfony/event-dispatcher-contracts v1.1.7
- don't install symfony/contracts v2.0.1|don't install symfony/event-dispatcher-contracts v1.1.7
- Installation request for symfony/contracts 2.0.1 -> satisfiable by symfony/contracts[v2.0.1].
- Installation request for symfony/event-dispatcher-contracts (locked at v1.1.7) -> satisfiable by symfony/event-dispatcher-contracts[v1.1.7].
Installation failed, reverting ./composer.json to its original content.
I have tried removing everything except composer.json and doing a reinstall, but ended up with the same error.
Another puzzling issue was that the symfony/event-dispatcher-contracts package is not explicitly locked in composer.json to a certain version, yet the error message specifies the v1.1.7 version, instead of the latest one, which is 2.0.1 as of this time. Looking into the composer.lock file, I see that there is a single require directive which includes this package, defined as symfony/event-dispatcher requires "symfony/event-dispatcher-contracts": "^1.1". This indeed forces the symfony/event-dispatcher-contracts to version 1.1.7, but I can't explain why it forces the package to be installed, instead of replacing it with symfony/contracts.
How can I add symfony/contracts to this project and remove the symfony/event-dispatcher-contracts dependecy (which is included in the symfony/contracts package).

Answer 1

symfony/contracts replaces symfony/event-dispatcher-contracts and other packages. Check which of your other packages requires this package through composer why symfony/event-dispatcher-contracts - I would assume that you need to update any of your other packages before you can start using the unified contracts package.
In your current setup, symfony/event-dispatcher requires the specific contracts in v1.1. The package to be installed replaces these contracts, but only those from v2. Installing symfony/contracts with the version constraint ^1.1 might be the best solution, if you don't want to upgrade symfony/event-dispatcher to v5 - this relies on v2 of the contracts