Jackson 3 parses YAML ~ as StringNode instead of NullNode

[neottil]

In Jackson 2, the special character ~ was parsed as a NullNode, while in Jackson 3 I get a StringNode with value ~. It seems that the default behavior has changed.

I tried several YAML mapper configurations, but I couldn’t find any setting that reproduces the Jackson 2 behavior.

The issue can be reproduced with the following test:

@Test
void tilde() throws JsonProcessingException {
    String rawDescriptor = """
         specVersion: v1
         kind: com.example.kind
         name: "mnp_up"
         state: ~
         description: "a description"
        """;

    tools.jackson.dataformat.yaml.YAMLMapper myYamlMapper = new YAMLMapper();
    JsonNode node1 = myYamlMapper.readValue(rawDescriptor, tools.jackson.databind.JsonNode.class);
    com.fasterxml.jackson.databind.ObjectMapper objectMapper = new com.fasterxml.jackson.databind.ObjectMapper(new YAMLFactory());
    com.fasterxml.jackson.databind.JsonNode node2 = objectMapper.readValue(rawDescriptor, com.fasterxml.jackson.databind.JsonNode.class);
    System.out.println("node1 state: " + node1.get("state").getNodeType() + "\nnode2 state: " + node2.get("state").getNodeType());
}

OUTPUT:
node1 state: STRING
node2 state: NULL

I couldn’t find anything about this in the migration documentation.

Since my application logic depends on parsing files that may contain this special character, I need to stay compatible with the behavior implemented in Jackson 2.

Is there a way to configure the Jackson 3 mapper to get the same result as in Jackson 2?

[pjfanning]

Can you close this and open an issue in https://github.com/FasterXML/jackson-dataformats-text (as opposed to a discussion)?

[neottil]

Issue #661 FasterXML/jackson-dataformats-text#661