Compiler Warning ASPIREEXPORT005

Version introduced: 13.2

[AspireUnion] requires at least 2 types, but 0 was specified.

This diagnostic warning is reported when an [AspireUnion] attribute is applied to a parameter with fewer than 2 types. A union type is only meaningful when it can represent two or more distinct types; using a union with a single type is equivalent to just using that type directly.

Example

The following code generates ASPIREEXPORT005:

C# — Integration.cs

[AspireExport("addResource")]
public static IResourceBuilder<ContainerResource> AddResource(
    IDistributedApplicationBuilder builder,
    [AspireUnion(typeof(string))] object name)  // Only 1 type specified
{
    return builder.AddContainer(name.ToString()!, "myimage");
}

To correct this warning

Either add a second type to the [AspireUnion] attribute, or remove the attribute and use the single type directly:

C# — Integration.cs

[AspireExport("addResource")]
public static IResourceBuilder<ContainerResource> AddResource(
    IDistributedApplicationBuilder builder,
    [AspireUnion(typeof(string), typeof(int))] object name)
{
    return builder.AddContainer(name.ToString()!, "myimage");
}

Suppress the warning

Suppress the warning with either of the following methods:

• Set the severity of the rule in the .editorconfig file.

  .editorconfig

  [*.{cs,vb}]
  dotnet_diagnostic.ASPIREEXPORT005.severity = none

  For more information about editor config files, see Configuration files for code analysis rules.

• Add the following PropertyGroup to your project file:

  C# project file

  <PropertyGroup>
      <NoWarn>$(NoWarn);ASPIREEXPORT005</NoWarn>
  </PropertyGroup>