Single character string containing special characters causes SyntaxErrorException

[akusei]

If you have a single character string with a special character (in my case an exclamation mark) YamlDotNet will throw a SyntaxErrorException.

commandPrefix: '!'
commandPrefix: "!"
commandPrefix: "\x21"
commandPrefix: !!str "!"

All of the above cause the exception when deserializing. Is this a bug or am I not understanding something about the YAML specification?

commandPrefix: "a!"

The above works correctly but that's because the exclamation mark is the 2nd character and not the 1st.

[aaubry]

This looks like a bug. I'll need some time to look into this. Could you send the full exception message, including the stack trace? Thanks

[akusei]

@aaubry

YamlDotNet.Core.SyntaxErrorException: (Line: 4, Col: 16, Idx: 88) - (Line: 4, Col: 17, Idx: 89): While parsing a tag, did not find expected tag URI.
at YamlDotNet.Core.Scanner.ScanTagUri(String head, Mark start)
at YamlDotNet.Core.Scanner.ScanTag()
at YamlDotNet.Core.Scanner.FetchTag()
at YamlDotNet.Core.Scanner.FetchNextToken()
at YamlDotNet.Core.Scanner.FetchMoreTokens()
at YamlDotNet.Core.Scanner.MoveNextWithoutConsuming()
at YamlDotNet.Core.Parser.GetCurrentToken()
at YamlDotNet.Core.Parser.ParseBlockMappingValue()
at YamlDotNet.Core.Parser.StateMachine()
at YamlDotNet.Core.Parser.MoveNext()
at YamlDotNet.Core.ParserExtensions.Allow[T](IParser parser)
at YamlDotNet.Core.ParserExtensions.Expect[T](IParser parser)
at YamlDotNet.Serialization.NodeDeserializers.ObjectNodeDeserializer.YamlDotNet.Serialization.INodeDeserializer.Deserialize(IParser parser, Type expectedType, Func`3 nestedObjectDeserializer, Object& value)
at YamlDotNet.Serialization.ValueDeserializers.NodeValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
at YamlDotNet.Serialization.ValueDeserializers.AliasValueDeserializer.DeserializeValue(IParser parser, Type expectedType, SerializerState state, IValueDeserializer nestedObjectDeserializer)
at YamlDotNet.Serialization.Deserializer.Deserialize(IParser parser, Type type)
at YamlDotNet.Serialization.Deserializer.Deserialize[T](String input)

[MaorDavidzon]

Any update?

[EdwardCooke]

I just tested this with the following code and it worked fine.

using YamlDotNet.Serialization;

var deserializer = new DeserializerBuilder()
    .Build();
var yamls = new string[]
{
    "commandPrefix: '!'",
    "commandPrefix: \"!\"",
    "commandPrefix: \"\x21\"",
    "commandPrefix: !!str \"!\"",
};
foreach (var yaml in yamls)
{
    var deserialized = deserializer.Deserialize<X>(yaml);
    Console.WriteLine(yaml + ":" + (deserialized.CommandPrefix ?? "NULL"));
}


public class X
{
    [YamlMember(Alias = "commandPrefix")]
    public string CommandPrefix { get; set; }
}

Results in:

commandPrefix: '!':!
commandPrefix: "!":!
commandPrefix: "!":!
commandPrefix: !!str "!":!