NDLRGEN034: Circular provider dependency detected¶

Diagnostic Info¶

Property	Value
ID	NDLRGEN034
Category	NexusLabs.Needlr.Generators
Severity	Error
Enabled	Yes

Description¶

This error is raised when providers reference each other in a way that creates a circular dependency. This would cause a stack overflow at runtime when attempting to construct the providers.

Example¶

Code that triggers the error¶

using NexusLabs.Needlr.Generators;

// ❌ NDLRGEN034: Circular dependency detected
[Provider]
public interface IProviderA
{
    IProviderB ProviderB { get; }  // References B
}

[Provider]
public interface IProviderB
{
    IProviderA ProviderA { get; }  // References A → Cycle!
}

How to fix¶

Break the circular dependency by restructuring your providers:

Option 1: Remove one of the references

[Provider]
public interface IProviderA
{
    IServiceFromB Service { get; }  // Reference the service directly, not the provider
}

[Provider]
public interface IProviderB
{
    IProviderA ProviderA { get; }
}

Option 2: Create a third provider for shared services

// Shared services used by both
[Provider]
public interface ISharedProvider
{
    ISharedService SharedService { get; }
}

[Provider]
public interface IProviderA
{
    ISharedProvider Shared { get; }
    IServiceA ServiceA { get; }
}

[Provider]
public interface IProviderB
{
    ISharedProvider Shared { get; }
    IServiceB ServiceB { get; }
}

Option 3: Use factory for deferred resolution

[Provider]
public interface IProviderA
{
    Func<IProviderB> ProviderBFactory { get; }  // Lazy resolution breaks the cycle
}

Why This Matters¶

Circular dependencies in constructor injection cause infinite recursion:

Constructing ProviderA requires ProviderB
Constructing ProviderB requires ProviderA
Constructing ProviderA requires ProviderB
... stack overflow

The analyzer detects these cycles at compile time before they become runtime failures.

Detection Scope¶

The analyzer detects:

Direct cycles: A → B → A
Indirect cycles: A → B → C → A