[Bug] Exception while de-serializing Uris

[nik-net]

If the stored value in a document is URI, then this code statement throws error (class BsonMapper.cs)

private void DeserializeDictionary(Type K, Type T, IDictionary dict, BsonDocument value)
        {
            var isKEnum = K.GetTypeInfo().IsEnum;
            foreach (var el in value.GetElements())
            {
               
                    var k = isKEnum ? Enum.Parse(K, el.Key) : Convert.ChangeType(el.Key, K); //Convert.ChangeType will throw error if K is Uri and el.Key is a string such as https://dev.azure.com
                    var v = this.Deserialize(T, el.Value);
                    dict.Add(k, v);
               }
        }

Modifying this line to

var k = isKEnum ? Enum.Parse(K, el.Key) : K == typeof(Uri) ? new Uri(el.Key) : Convert.ChangeType(el.Key, K);

works.

[lbnascimento]

@nik-net This is not a bug in LiteDB, but a limitation in Convert.ChangeType: all this method does is try to cast an object to another type, and there is no valid cast from string to Uri (LiteDB serializes Uri as their string representation). It is possible to create a Uri from a string with the Uri constructor, and that is what your second example does, but ChangeType is not aware of that.

[nik-net]

@nik-net This is not a bug in LiteDB, but a limitation in Convert.ChangeType: all this method does is try to cast an object to another type, and there is no valid cast from string to Uri (LiteDB serializes Uri as their string representation). It is possible to create a Uri from a string with the Uri constructor, and that is what your second example does, but ChangeType is not aware of that.

Thank you, yes I understand that this is due to ChangeType's inability to convert a string to it's URI representation. Given this known limitation would you be looking to handle this edge case in the code?

[lbnascimento]

@nik-net Sorry, for whatever reason I didn't realize the DeserializeDictionary was in our BsonMapper, I thought it was some code of yours. I'll add your fix.