PROJ005: UseProjection references invalid type

Field	Value
Code	PROJ005
Severity	Error

Message

UseProjection attribute on GSI '{0}' references non-existent or invalid projection type '{1}'

Description

UseProjection attribute must reference a valid projection model type. When you apply [UseProjection(typeof(...))] to a GSI definition, the referenced type must be a class decorated with [DynamoDbProjection].

This diagnostic is emitted when the type referenced in [UseProjection] does not exist, is not a projection class, or cannot be resolved at compile time. Verify that the type name is correct and that the class has the [DynamoDbProjection] attribute.

Example

The following code triggers this diagnostic:

[DynamoDbTable("Orders")]
public partial class Order
{
    [PartitionKey]
    [DynamoDbAttribute("pk")]
    public string Pk { get; set; } = string.Empty;

    // PROJ005: 'InvalidProjection' is non-existent or invalid
    [GsiPartitionKey("status-index")]
    [UseProjection(typeof(InvalidProjection))]
    [DynamoDbAttribute("status")]
    public string Status { get; set; } = string.Empty;
}

Fix

The corrected version:

[DynamoDbTable("Orders")]
public partial class Order
{
    [PartitionKey]
    [DynamoDbAttribute("pk")]
    public string Pk { get; set; } = string.Empty;

    [GsiPartitionKey("status-index")]
    [UseProjection(typeof(OrderSummary))]
    [DynamoDbAttribute("status")]
    public string Status { get; set; } = string.Empty;
}

[DynamoDbProjection(typeof(Order))]
public partial class OrderSummary
{
    [DynamoDbAttribute("status")]
    public string Status { get; set; } = string.Empty;
}