Composer require and dependency management in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of composer show after requiring a package?

You run composer require monolog/monolog in your PHP project. Then you run composer show monolog/monolog. What output will you see?

A Outputs only the version number of monolog/monolog

B Displays package name, version, description, and dependencies of monolog/monolog

C Lists all packages except monolog/monolog

D Shows an error: Package monolog/monolog not found

💡 Hint

Think about what composer show does for a specific package.

The composer show monolog/monolog command displays detailed info about the installed package, including its name, version, description, and dependencies.

❓ Predict Output

intermediate

What happens if you run composer require with a non-existent package?

You run composer require vendor/nonexistent-package in your project. What will happen?

A Composer adds the package to composer.json but does not install it

B Composer installs an empty package with no files

C Composer shows an error: Could not find package vendor/nonexistent-package

D Composer installs the latest stable version of a similar package automatically

💡 Hint

Composer only installs packages that exist in repositories it knows.

If the package does not exist, Composer will stop and show an error message saying it could not find the package.

🔧 Debug

advanced

Why does composer install not install new packages added manually to composer.json?

You manually add a new package to composer.json under require but running composer install does not install it. Why?

A Because you must run <code>composer update</code> to install new packages after editing composer.json manually

B Because the package is already installed globally and Composer ignores local installs

C Because the package version constraint is invalid and Composer skips it silently

D Because <code>composer update</code> only updates existing packages, not install new ones added manually

💡 Hint

Think about the difference between composer install and composer update.

composer install installs packages listed in composer.lock. If you manually add a package to composer.json, you must run composer update to install it and update composer.lock.

📝 Syntax

advanced

Which composer.json snippet correctly requires a package with a version constraint?

Choose the correct require section snippet to require guzzlehttp/guzzle version 7.0 or higher but less than 8.0.

A "require": { "guzzlehttp/guzzle": "^7.0" }

B "require": { "guzzlehttp/guzzle": ">=7.0,<8.0" }

C "require": { "guzzlehttp/guzzle": "7.*" }

D "require": { "guzzlehttp/guzzle": ">=7.0 <8.0" }

💡 Hint

Composer uses caret (^) for compatible version ranges.

The caret operator ^7.0 means any version from 7.0 up to but not including 8.0, which matches the requirement.

🚀 Application

expert

How to require a package only for development using composer?

You want to add phpunit/phpunit as a dependency only for development, not for production. Which command do you run?

A composer require phpunit/phpunit --optimize-autoloader

B composer require phpunit/phpunit --update-no-dev

C composer require phpunit/phpunit --no-dev

D composer require phpunit/phpunit --dev

💡 Hint

Think about the flag that marks a package as development-only.

The --dev flag adds the package to the require-dev section, so it is installed only in development environments.