dotnet/efcore · error · InvalidOperationException

'PropagatesNullability' cannot be set on parameter

Error message

'PropagatesNullability' cannot be set on parameter '{parameterName}' of DbFunction '{functionName}' since function does not represent a scalar function.

What it means

Nullability propagation (whether a NULL parameter makes the result NULL) is only meaningful for scalar DbFunctions. DbFunctionParameter.SetPropagatesNullability throws when called on a parameter of a non-scalar (TVF) function, because row-set results do not have a single NULL outcome.

Solutions

1. Remove the PropagatesNullability call from any parameter belonging to a TVF DbFunction.
2. If nullability propagation is required, change the function to a scalar return so per-parameter propagation is valid.

Example fix

// before
public IQueryable<Order> Search(string term) => throw new NotSupportedException();
modelBuilder.HasDbFunction(typeof(AppDb).GetMethod(nameof(Search)))
    .HasParameter("term").PropagatesNullability();

// after
modelBuilder.HasDbFunction(typeof(AppDb).GetMethod(nameof(Search)));
// parameters of a TVF cannot be marked as propagating nullability

var fn = modelBuilder.HasDbFunction(typeof(AppDb).GetMethod(nameof(AppDb.Search))!).Metadata;
if (!fn.IsScalar)
{
    return; // do not configure PropagatesNullability on TVF parameters
}

static bool ParameterSupportsNullability(IReadOnlyDbFunction fn) => fn.IsScalar;

When it happens

Trigger: Calling HasParameter(name).PropagatesNullability(...) or SetPropagatesNullability on a parameter of a method that returns IQueryable<T>; common when sharing configuration helpers between scalar and TVF functions.

Common situations: Building a fluent helper that configures all DbFunctions uniformly and including PropagatesNullability; refactor converting a scalar function to a TVF while leaving per-parameter configuration in place.

Related errors

• 'IsNullable' cannot be set on DbFunction
• Custom translation cannot be set on the DbFunction
• The DbFunction ' ' does not have a parameter named ' '.
• The DbFunction ' ' has an invalid return type ' '…
• The DbFunction ' ' defined on type ' ' must be either a…

AI-assisted analysis of dotnet/efcore@3a2006ef56 (2026-08-11). Data as JSON: /api/errors/c52f4e070f6a8a99. Report an issue: GitHub.

Appendix: source

Thrown at src/EFCore.Relational/Metadata/Internal/DbFunctionParameter.cs:216

    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    public virtual bool PropagatesNullability
    {
        get => _propagatesNullability;
        set => SetPropagatesNullability(value, ConfigurationSource.Explicit);
    }

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    public virtual bool SetPropagatesNullability(bool propagatesNullability, ConfigurationSource configurationSource)
    {
        if (!Function.IsScalar)
        {
            throw new InvalidOperationException(
                RelationalStrings.NonScalarFunctionParameterCannotPropagatesNullability(Name, Function.Name));
        }

        _propagatesNullability = propagatesNullability;
        _propagatesNullabilityConfigurationSource = configurationSource.Max(_storeTypeConfigurationSource);

        return propagatesNullability;
    }

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    public virtual ConfigurationSource? GetPropagatesNullabilityConfigurationSource()
        => _propagatesNullabilityConfigurationSource;

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