WHIZ059: GUID Interception Suppressed¶

Verified by tests

GuidInterceptorGeneratorTests — library CI run #37346231411 (2026-10-05)

Severity: Info Category: Source Generation

Description¶

This informational diagnostic is reported when a GUID creation call could be intercepted but was suppressed via the [SuppressGuidInterception] attribute. This indicates intentional opt-out from TrackedGuid wrapping.

The diagnostic is reported whenever the generator runs — even if the MSBuild property WhizbangGuidInterceptionEnabled is not set (the property only gates whether interceptor code is generated for the non-suppressed calls).

Suppression via #pragma warning disable WHIZ055/WHIZ056 around a call disables interception silently — those calls produce no WHIZ059 (only attribute-based suppression is reported).

Diagnostic Message¶

Interception suppressed for System.Guid.NewGuid at /src/MyApp/TestData.cs:15 via SuppressGuidInterceptionAttribute on method

The last part identifies the suppression scope: on method, on local function, on type, or on assembly.

Why Suppress Interception¶

Common reasons to suppress GUID interception:

1. Test Fixtures¶

Test Fixtures

using Whizbang.Core;

[SuppressGuidInterception]
public static class TestData {
  // Tests may need raw GUIDs for fixture data
  public static readonly Guid KnownOrderId = Guid.Parse("550e8400-e29b-41d4-a716-446655440000");

  public static Guid CreateTestGuid() {
    return Guid.NewGuid();  // WHIZ059 reported here
  }
}

2. Integration with External Systems¶

Integration with External Systems

public class ExternalApiClient {
  [SuppressGuidInterception]
  public Guid CreateExternalRequestId() {
    // External system expects raw GUID format
    return Guid.NewGuid();  // WHIZ059 reported here
  }
}

3. Performance-Critical Paths¶

Performance-Critical Paths

public class HighThroughputProcessor {
  [SuppressGuidInterception]
  public Guid CreateTransientId() {
    // Avoid TrackedGuid overhead for transient IDs
    return Guid.NewGuid();  // WHIZ059 reported here
  }
}

4. Legacy Code Migration¶

Legacy Code Migration

[SuppressGuidInterception]
public class LegacyService {
  // Gradual migration - suppress for now
  public Guid CreateId() => Guid.NewGuid();
}

Suppression Scopes¶

The [SuppressGuidInterception] attribute can be applied at different scopes:

Method Scope¶

Method Scope

public class MyService {
  [SuppressGuidInterception]
  public Guid CreateRawGuid() {
    return Guid.NewGuid();  // Suppressed
  }

  public Guid CreateTrackedGuid() {
    return Guid.NewGuid();  // Intercepted
  }
}

Class Scope¶

Class Scope

[SuppressGuidInterception]
public class TestFixtures {
  public Guid Id1 => Guid.NewGuid();  // Suppressed
  public Guid Id2 => Guid.NewGuid();  // Suppressed
}

Local Function Scope¶

Local Function Scope

public Guid CreateId() {
  [SuppressGuidInterception]
  static Guid CreateRaw() => Guid.NewGuid();  // Suppressed

  return CreateRaw();
}

Assembly Scope¶

Assembly Scope

// In AssemblyInfo.cs or any file
[assembly: SuppressGuidInterception]
// All GUID calls in this assembly are suppressed

Suppressing This Diagnostic¶

If you don't want to see WHIZ059 diagnostics:

Project-Level¶

Project-Level

<PropertyGroup>
  <NoWarn>$(NoWarn);WHIZ059</NoWarn>
</PropertyGroup>

Code-Level¶

Code-Level

#pragma warning disable WHIZ059
[SuppressGuidInterception]
public Guid CreateId() => Guid.NewGuid();
#pragma warning restore WHIZ059

WHIZ058 - GUID call intercepted (the inverse - when interception happens)
WHIZ055 - Warning for Guid.NewGuid() usage
WHIZ056 - Warning for Guid.CreateVersion7() usage