Symfony "Cannot autowire service ... argument references ... but no such service exists" in CI

By Daniel Zoghalchali·Latchkey

Autowiring tried to resolve a constructor argument by its type hint and found no service registered for that class or interface. Symfony cannot guess which implementation to inject, so container compilation fails.

What this error means

Compilation fails with "Cannot autowire service \"X\": argument \"$y\" of method \"__construct()\" references interface \"Z\" but no such service exists." Symfony often suggests aliasing the interface.

Cannot autowire service "App\Service\Invoicer": argument "$client" of method
"__construct()" references interface "App\Client\PaymentClientInterface" but no such
service exists. Did you create a class that implements this interface?

Diagnose it: version, extensions, and limits

php -v
php -m
php -i | grep -E "memory_limit|max_execution_time|error_reporting"

# a runner default is often far tighter than your local php.ini
php -d memory_limit=-1 vendor/bin/<tool>

Common causes

An interface has no service alias

You type-hinted an interface but never told the container which concrete service implements it, so autowiring has nothing to inject.

The class is excluded from autoloading in this env

A resource/exclude rule in services.yaml, or a bundle absent in the test env, means the implementing class is never registered as a service.

How to fix it

Alias the interface to a concrete service

1. Pick the implementation that should be injected.
2. Add an alias binding the interface id to that service in services.yaml.
3. Re-run container compilation to confirm autowiring resolves it.

# config/services.yaml
services:
    App\Client\PaymentClientInterface: '@App\Client\StripePaymentClient'

Bind a scalar or named argument explicitly

For arguments autowiring cannot infer (a string, a specific instance), bind them by name so the container stops trying to autowire them.

services:
    _defaults:
        bind:
            $client: '@App\Client\StripePaymentClient'

How to prevent it

• Alias every injectable interface to a concrete implementation.
• Run lint:container in CI so autowiring gaps fail fast.
• Keep the same service registration rules across dev and test environments.

Frequently asked questions

Related guides

References

• Composer documentation
• GitHub Actions documentation