DYNDB020: Circular reference detected

Field	Value
Code	DYNDB020
Severity	Error

Message

Entity '{0}' has circular references that cannot be serialized to DynamoDB

Description

Entities with circular references cannot be properly serialized to DynamoDB format. DynamoDB stores items as flat attribute maps and nested maps, which cannot represent circular object graphs.

Example

The following code triggers this diagnostic:

[DynamoDbEntity]
public partial class TreeNode
{
    [DynamoDbAttribute("name")]
    public string Name { get; set; } = string.Empty;

    [DynamoDbMap]
    [DynamoDbAttribute("parent")]
    public TreeNode Parent { get; set; } = null!;
}

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

    [DynamoDbMap]
    [DynamoDbAttribute("root")]
    public TreeNode Root { get; set; } = new();
}

Fix

The corrected version:

[DynamoDbEntity]
public partial class TreeNode
{
    [DynamoDbAttribute("name")]
    public string Name { get; set; } = string.Empty;

    [DynamoDbAttribute("parentId")]
    public string ParentId { get; set; } = string.Empty;
}

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

    [DynamoDbMap]
    [DynamoDbAttribute("root")]
    public TreeNode Root { get; set; } = new();
}