Error running the `setup:di:compile` command manually

This article provides a fix for when running the setup:di:compile command manually on Magento Commerce (Cloud) fails with an error (see the Issue section below) because the command tries to access the var/di and var/generation directories, which are read-only.

This is an expected behavior: the setup:di:compile command should not be run manually on Magento Commerce (Cloud) since it is executed automatically during the deployment process.

We strongly do not recommend running setup:di:compile manually, but if you have a reason to do so, you need to set the following environment variable to make var/di and var/generation folders writable:

GENERATED_CODE_SYMLINK = disabled

Note that with code symlink generation disabled, the deployment downtime increases.

The build variable GENERATED_CODE_SYMLINK was removed for Magento Commerce (Cloud) 2.2 and later.

Affected versions

• Magento Commerce (Cloud) 2.0.X, 2.1.X

Issue

Running the the setup:di:compile command manually fails with the following error:

web@<path>:~$ php bin/magento setup:di:compile
The file "/app/var/generation/<path/to/resource>" cannot be deleted Warning!unlink(/app/var/generation/Composer/Console/ApplicationFactory.php): Read-only file system#0 /app/vendor/magento/framework/Filesystem/Driver/File.php(405): Magento\Framework\Filesystem\Driver\File->deleteFile('/app/var/genera...')
#1 /app/vendor/magento/framework/Filesystem/Driver/File.php(403): Magento\Framework\Filesystem\Driver\File->deleteDirectory('/app/var/genera...')
#2 /app/vendor/magento/framework/Filesystem/Driver/File.php(403): Magento\Framework\Filesystem\Driver\File->deleteDirectory('/app/var/genera...')
#3 /app/setup/src/Magento/Setup/Console/CompilerPreparation.php(68): Magento\Framework\Filesystem\Driver\File->deleteDirectory('/app/var/genera...')
#4 /app/vendor/magento/framework/Console/Cli.php(65): Magento\Setup\Console\CompilerPreparation->handleCompilerEnvironment()
#5 /app/bin/magento(22): Magento\Framework\Console\Cli->__construct('Magento CLI')
#6 {main}
PHP Fatal error:  Uncaught Error: Class 'Cli' not found in /app/bin/magento:31
Stack trace:
#0 {main}
  thrown in /app/bin/magento on line 31
Fatal error: Uncaught Error: Class 'Cli' not found in /app/bin/magento:31
Stack trace:
#0 {main}
  thrown in /app/bin/magento on line 31

Cause

The error occurs because the setup:di:compile command tries to access the var/di and var/generation directories, which are read-only.

It is not a defect but an expected behavior on cloud environments. You should not run setup:di:compile manually since this command is being executed during the deployment process. The Magento code cannot be changed on the fly (because it is located in the read-only directories), so there is no need to recompile var/di and var/generation: there is no difference with files generated during deployment.

Solution

Make the var/di and var/generation directories writable by setting the environment variable below:

GENERATED_CODE_SYMLINK = disabled

This allows you to run setup:di:compile manually, but the deployment process lasts longer.

More information on DevDocs

Environment variables are covered in the articles of the Manage variables section.

Particular topics you might be interested in:

• Magento Commerce (Cloud) variables
• Add environment variables via CLI and the Project Web Interface