Fix for issue #11 causes inconsistent with default JsonPropertyOrder behavior

[Spikhalskiy]

For this two classes will be generated schemas with different fields order. Fix for Issue #11 not only broke compatibility - it make inconsistent default behavior of CsvMapper with default JsonPropertyOrder value.

    class Point {
        public int y;
        public int x;
    }

    @JsonPropertyOrder
    public static class PointWithAnnotation extends Point {}

[cowtowncoder]

Um... why would you use empty @JsonPropertyOrder here tho?

[Spikhalskiy]

@cowtowncoder Just to illustrate that behavior for this two classes should be the same

[cowtowncoder]

Unfortunately, due to Java annotations not having concept of 'null' or 'not define' value, they are not.
@JsonPropertyOrder is semantically same as @JsonPropertyOrder(alphabetic=false) because of default value (and not defining default would meka alphabetic required one to fill.

So while unfortunate, I am not sure much can be done here. Annotations do not allow use of Boolean (for example) -- many JavaSoft architects are heavily anti-null, and in my opinion this is one place where it is really unfortunate as use of default is very difficult with annotations.

[Spikhalskiy]

@cowtowncoder Behavior for this two situations must be the same. Because I just add annotation with default value which is this situation should not change anything. No specified order == default order. So, default befavior of CsvMapper in case of no JsonPropertyOrder should be == JsonPropertyOrder with default value - "alphabetic=false". As for me fix and Issue #11 was broking + illegal without changing default behavior thru all components and default value in this annotation.

[cowtowncoder]

Ok. If the behavior is not the same that does sound wrong. I'll see what gives that.

I would suggest, as an additional point, that if using CSV you really should always either specify explicit ordering, or default to using alphabetic ordering. The way 'alphabetic' works for @JsonPropertyOrder is problematic, but I do not see a way to resolve that part, given that most use cases are for explicit ordering and not for enabling alphabetic ordering.

[cowtowncoder]

Actually no. I disagree.

Point has no annotation, so it defaults to settings apply alphabetic ordering, as CsvMapper instructs as the default.

PointWithAnnotation overrides ordering with @JsonPropertyOrder with "not alphabetic" setting (which is not very useful, agreed, but this is what original setting said). It happens to then produce ordering based on field order, although that is not guaranteed.

One possibility for 2.6 would be to re-define semantics of @JsonPropertyOrder.alphabetic so that 'true' would force sorting override, but 'false' would not change anything. Since it does not seem very useful to force use of an arbitrary, possibly unstable ordering this change could work, even if it is not ideal.
If this change was made it would change behavior to match your expectation. I also do not think it would cause breakage as I do not see value in explicit @JsonPropertyOrder(alphabetic=false).

[cowtowncoder]

As per

FasterXML/jackson-databind#840

this is now fixed for 2.6.0; will be in 2.6.0-rc3.