DynamoDBv2: Document.FromAttributeMap Fails to Handle M or L if NULL is set to false

[david-beckman]

Steps to reproduce:

1. Populate a attribute map Dictionary<string, AttributeValue> such that at least one of the AttributeValue instances has M or L set. Also update said AttributeValue such that NULL is false. An easy way to do that is via JSON Deserialization:

{
    "Account": {
        "B": null,
        "BOOL": false,
        "IsBOOLSet": false,
        "BS": [],
        "L": [],
        "IsLSet": false,
        "M": {
            "Name": {
                "B": null,
                "BOOL": false,
                "IsBOOLSet": false,
                "BS": [],
                "L": [],
                "IsLSet": false,
                "M": {},
                "IsMSet": false,
                "N": null,
                "NS": [],
                "NULL": false,
                "S": "Test Account",
                "SS": []
            }
        },
        "IsMSet": true,
        "N": null,
        "NS": [],
        "NULL": false,
        "S": null,
        "SS": []
    }
}

2. Create a Document from this attribute map via Document.FromAttributeMap

Expected Behavior:
The value is set to the correct Document instance

Actual Behavior:
The value is set to DynamoDBNull

Technical Details
In the AttributeValueToDynamoDBEntry method, TryToDynamoDBNull is called prior to TryToDynamoDBList or TryToDocument and it is returning DynamoDBNull incorrectly. The call to attributeValue.IsSetNULL should be attributeValue.NULL instead.

[david-beckman]

Here is a unit test that will expose the issue:

#r "nuget:AWSSDK.DynamoDBv2/3.7.0.45"
#r "nuget:xunit/2.4.1"

using System.Text.Json;

using Amazon.DynamoDBv2.DocumentModel;
using Amazon.DynamoDBv2.Model;

using Xunit;

var mapJson = @"{
    ""Account"": {
        ""B"": null,
        ""BOOL"": false,
        ""IsBOOLSet"": false,
        ""BS"": [],
        ""L"": [],
        ""IsLSet"": false,
        ""M"": {
            ""Name"": {
                ""B"": null,
                ""BOOL"": false,
                ""IsBOOLSet"": false,
                ""BS"": [],
                ""L"": [],
                ""IsLSet"": false,
                ""M"": {},
                ""IsMSet"": false,
                ""N"": null,
                ""NS"": [],
                ""NULL"": false,
                ""S"": ""Test Account"",
                ""SS"": []
            }
        },
        ""IsMSet"": true,
        ""N"": null,
        ""NS"": [],
        ""NULL"": false,
        ""S"": null,
        ""SS"": []
    }
}";

var map = JsonSerializer.Deserialize<Dictionary<string, AttributeValue>>(mapJson);
var doc = Document.FromAttributeMap(map);

Assert.NotNull(doc);
Assert.True(doc.ContainsKey("Account"));
Assert.NotNull(doc["Account"]);

var accountDoc = doc["Account"].AsDocument();
Assert.NotNull(accountDoc);
Assert.True(accountDoc.ContainsKey("Name"));
Assert.Equal("Test Account", accountDoc["Name"]);

[ashishdhingra]

@david-beckman I'm able to see that Document with Key Account is returned with value Amazon.DynamoDBv2.DocumentModel.DynamoDBNull, i.e., there is it is not of type Amazon.DynamoDBv2.DocumentModel.Document. Removing "NULL": false from Account key works fine.

[ashishdhingra]

Also revisit #1980 since it appears to be a related issue.

[david-beckman]

I re-ran that unit test above and it now passes; it looks like it was fixed between 3.7.3.23 & 3.7.3.24. I am closing this issue.

[github-actions]

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