READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE doesn't work with empty strings ("")

[unintended]

version: 2.12.13

public enum PetType {
  @JsonEnumDefaultValue
  cat,
  dog
}

public class Pet {
  private PetType type;
}

deserializing of {type: "fish"} results in type == PetType.cat
but deserializing of {type: ""} results in coercion failure:

com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot coerce empty String ("") to PetType value (but could if coercion was enabled using CoercionConfig)

Looks like CoercionConfigs takes precedence before READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE. Enabling ACCEPT_EMPTY_STRING_AS_NULL_OBJECT makes all "" enums nulls.

Expected behavior: empty strings are mapped to default enum value if READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE is enabled and ACCEPT_EMPTY_STRING_AS_NULL_OBJECT is not enabled.

[cowtowncoder]

Interesting! Thank you for reporting this, it does sounds like a bug for an edge case, caused by new coercion configuration settings in 2.12.