NDLRGEN004: No factory parameters are injectable¶

Diagnostic Info¶

Property	Value
ID	NDLRGEN004
Category	NexusLabs.Needlr.Generators
Severity	Warning
Enabled	Yes

Description¶

This warning is raised when a class marked with [GenerateFactory] has a constructor where no parameters are injectable types. The factory will still work, but it provides low value since there are no dependencies to inject - you could simply use new directly.

Example¶

Code that triggers the warning¶

using NexusLabs.Needlr.Generators;

// ⚠️ NDLRGEN004: No parameters are injectable, factory provides low value
[GenerateFactory]
public class ConnectionString
{
    public ConnectionString(string server, int port, string database)
    {
        // All parameters are runtime - nothing to inject
    }
}

How to fix¶

Either remove the [GenerateFactory] attribute and use new directly, or add an injectable dependency:

Option 1: Remove the attribute and use new

// Just use new directly - no factory needed
public class ConnectionString
{
    public ConnectionString(string server, int port, string database) { }
}

// Usage
var conn = new ConnectionString("localhost", 5432, "mydb");

Option 2: Add an injectable dependency

[GenerateFactory]
public class ConnectionString
{
    public ConnectionString(IConfiguration config, string server, int port, string database)
    {
        // Now the factory provides value - it injects IConfiguration
    }
}

Why This Matters¶

The primary purpose of factory generation is to partition constructor parameters into those that can be auto-injected and those that must be provided at runtime. If there's nothing to inject, the factory is just an extra layer of indirection.

When to Suppress¶

You might intentionally want a factory for a type with no injectable dependencies if:

You want consistent factory patterns across your codebase
You anticipate adding injectable dependencies later
You prefer resolving factories from DI for consistency

#pragma warning disable NDLRGEN004
[GenerateFactory]
public class ConnectionString { /* ... */ }
#pragma warning restore NDLRGEN004