GQL013: OneOf fields must be nullable

	Value
Rule ID	GQL013
Category	Usage
Default severity	Error
Enabled by default	Yes
Code fix provided	No
Introduced in	v8.0

Cause

This rule triggers when any of the fields defined by the OneOf input graph type is not nullable.

Rule description

All the fields defined by the OneOf input graph type must be nullable. The rule runs on the code-first input types when IInputObjectGraphType.IsOneOf = true; and type-first models decorated with [OneOf] attribute. If the field is decorated with the [Ignore] attribute the rule violation is not reported.

How to fix violations

Make all the fields in the OneOf graph type nullable.

Example of a violation

Code-first:

public class UserIdentifierInputGraphType : InputObjectGraphType<UserIdentifier>
{
    public UserIdentifierInputGraphType()
    {
        IsOneOf = true;

        Field<NonNullGraphType<IdGraphType>>("id");
        Field(x => x.Name); // 'nullable' is false by default
        Field(x => x.NickName, nullable: false);
        Field(x => x.FullName, type: typeof(NonNullGraphType<StringGraphType>));
        // 'nullable' is ignored when 'type' is defined
        Field(x => x.Email, nullable: true, type: typeof(NonNullGraphType<StringGraphType>));
    }
}

Type-first:

[OneOf]
public class UserIdentifier
{
    // non-nullable value type
    public int Id { get; set; }

    // Null Reference Types are fully supported
#nullable enable
    public string Name { get; set; }
#nullable restore
}

Example of how to fix

Make all fields nullable

Code-first:

public class UserIdentifierInputGraphType : InputObjectGraphType<UserIdentifier>
{
    public UserIdentifierInputGraphType()
    {
        IsOneOf = true;

        Field<IdGraphType>("id");
        Field(x => x.Name, nullable: true); // 'nullable' is false by default
        Field(x => x.NickName, nullable: true);
        Field(x => x.FullName, type: typeof(StringGraphType));
        // 'nullable' is ignored when 'type' is defined
        Field(x => x.Email, nullable: true, type: typeof(StringGraphType));
    }
}

Type-first:

[OneOf]
public class UserIdentifier
{
    public int? Id { get; set; }

    // Nullable Reference Types (NRT) are fully supported
#nullable enable
    public string? Name { get; set; }
#nullable restore
}

Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable GQL013
// The code that's violating the rule is on this line.
#pragma warning restore GQL013

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.cs]
dotnet_diagnostic.GQL013.severity = none

For more information, see How to suppress code analysis warnings.

GQL014: OneOf fields must not have default value