`JsonParserSequence` read methods no longer use Parsers beyond the first

[stefnoten-aca]

The read methods on JsonParserSequence previously correctly used all parsers in the sequence, however after upgrading to Jackson 3.x they only use the first one. This caused corrupt parsing in our application, dropping parts of the input json. We had a custom deserializer using the same mechanism as AsPropertyTypeDeserializer (which scans ahead for an @type property, then deserializing with a JsonParserSequence of a TokenBuffer and the actual parser).

Cause

Jackson 2.x - inherited from JsonParser superclass:

public <T extends TreeNode> T readValueAsTree() throws IOException {
    return (T) _codec().readTree(this); // passing this causes all Parsers in the sequence to be used
}

Jackson 3.x - overridden by JsonParserDelegate superclass in 8ee7d0f, becoming incorrect for JsonParserSequence:

public <T extends TreeNode> T readValueAsTree() throws IOException {
    return delegate.readValueAsTree(); // delegate is set to parsers[0] for JsonParserSequence
}

Workaround

Instead of parser.readValueAsTree() (or other read methods), use context.readTree(parser)

[cowtowncoder]

Sounds like a flaw indeed. Would it be possible to come up with a test case (like unit test) to reproduce?

[cowtowncoder]

Was able to, I think, generate a test.