Infer @JsonCreator(mode = Mode.DELEGATING) from use of @JsonValue) · Issue #3654 · FasterXML/jackson-databind (original) (raw)

(note: continuation of [some issue but wrote originally down wrong])

Although @JsonValue is currently only used for serialization purposes, it seems it could be used for deciding on one otherwise ambiguous use case: that of 1-argument Creator method without mode property.
This case currently uses heuristics, such that:

1. If there is explicit name specified for Creator argument (like @JsonProperty), Mode.PROPERTIES is used
2. If there is a named non-creator-property matching Creator argument name, Mode.PROPERTIES is used -- this is typically the case for Record types
3. Otherwise Mode.DELEGATING is used (unless different default choice specified)

However: use of @JsonValue would strongly suggest that as the second step (after explicit name for Creator argument) we should consider its existence to select Mode.DELEGATING instead.