microsoft/aspire · error · NotSupportedException

The scope value type

Error message

The scope value type {scopeValue.GetType()} is not supported.

What it means

ResolveScopeValueAsync supports only string and IValueProvider scope values; any other object type hits the NotSupportedException fallback arm. The message includes the concrete runtime type so developers know what leaked into the scope property.

Solutions

1. Convert the value to a string before assigning it as the scope (e.g. .ToString() or reference type/value provider helpers).
2. Use builder.CreateResourceBuilder/parameter references so the scope is an IValueProvider instead of a raw object.
3. If using a custom value type, implement IValueProvider (or wrap it in one) so it resolves via GetValueAsync.
4. Check the reported type name in the message and map it to the supported string/IValueProvider forms.

Example fix

// before
resource.Scope = new ResourceId("/subscriptions/..."); // unsupported type

// after
resource.Scope = "/subscriptions/.../resourceGroups/rg"; // or an IValueProvider

static bool IsSupportedScopeValue(object? value) => value is string or IValueProvider;

static string? ResolveScopeSync(object scopeValue) => scopeValue switch
{
    string s => s,
    IValueProvider vp => vp.GetValueAsync(default).GetAwaiter().GetResult() as string,
    _ => null
};

try
{
    await provisioner.GetOrCreateResourceAsync(resource, ct);
}
catch (NotSupportedException ex) when (ex.Message.Contains("scope value type"))
{
    logger.LogError(ex, "Unsupported scope type assigned; use a string or IValueProvider.");
}

When it happens

Trigger: Assigning an unsupported object (e.g. an endpoint reference, custom wrapper type, or IResource instead of an IValueProvider/string) to a resource's scope setting consumed by ResolveScopeValueAsync.

Common situations: Passing a strongly-typed value (ResourceId, URI object, builder expression) where a string or IValueProvider is expected; upgrading Aspire where scope APIs tightened; hand-written custom scope types.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• A of type cannot be assigned to a BicepValue< >.
• Expected a string, integer, or
• Expected a literal or .
• The Azure resource scope value cannot be null.
• The Azure scope value type

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/a11cd8bf7d9e9178. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.Azure/Provisioning/Provisioners/BicepProvisioner.cs:1289

        return details.Count == 0 ? string.Empty : $" ({string.Join("; ", details)})";

        void AddDetail(string name, string? value)
        {
            if (!string.IsNullOrEmpty(value))
            {
                details.Add($"{name}: {value}");
            }
        }
    }

    private static async Task<string> ResolveScopeValueAsync(object scopeValue, CancellationToken cancellationToken)
    {
        return scopeValue switch
        {
            string value => value,
            IValueProvider valueProvider => await valueProvider.GetValueAsync(cancellationToken).ConfigureAwait(false) ?? throw new InvalidOperationException("The Azure resource scope value cannot be null."),
            _ => throw new NotSupportedException($"The scope value type {scopeValue.GetType()} is not supported.")
        };
    }

    private async Task<bool> TryCancelDeploymentAsync(IArmDeploymentCollection deployments, string deploymentName, ILogger resourceLogger, bool treatMissingOrInactiveAsCanceled)
    {
        try
        {
            await deployments.CancelAsync(deploymentName, CancellationToken.None).ConfigureAwait(false);
            resourceLogger.LogInformation("Cancellation requested for Azure deployment {DeploymentName}.", deploymentName);
            return true;
        }
        catch (RequestFailedException ex) when (treatMissingOrInactiveAsCanceled && (ex.Status == 404 || ex.Status == 409))
        {
            logger.LogInformation(ex, "Azure deployment {DeploymentName} was already absent or no longer active during cancellation.", deploymentName);
            resourceLogger.LogInformation("Azure deployment {DeploymentName} was already absent or no longer active during cancellation.", deploymentName);
            return true;
        }
        catch (RequestFailedException ex)

View on GitHub (pinned to 25830f84bd)