(csv) Missing null writes when writing Object[] values

[cowtowncoder]

(moved from FasterXML/jackson-dataformat-csv#116 by @georgewfraser)

When writing arrays to CSV, if there is a null, columns get written out of order. Reproduced in 2.7.1 with this test: https://gist.github.com/georgewfraser/164647fbaca61aadf9ee

[cowtowncoder]

More likely related to #116 (?): looks like nulls for "array in array" are suppressed. This could be somewhat problematic even for other entries since "null value" would not get written.

[daliclass]

@cowtowncoder Hey, Is anyone working on this I would be happy to pick it up

Added a gist for the current behaviour in 2.9.0 and what I think the desired behaviour should be

https://gist.github.com/daliclass/19507eb79939e6ad716b30cd241c612b

[ganchurin]

@cowtowncoder Is there any workaround for the issue?

[cowtowncoder]

@ganchurin not aware of work-arounds unfortunately. If anyone has time to look into this, I would be happy to help validate fix, integrate, but right now I do not have time in short term. I will add this as something to (re-)evaluate tho as it is an important issue.

[gimiz]

Workaround:
Before writing change null value to an empty string. In not-quoted CSV empty string looks the same as null (separator only).
If you need to use qouteChar, set CsvGenerator.Feature.ALWAYS_QUOTE_STRINGS to false to use quotes only when necessary. Empty string will stay not-quoted.
If you need all values quoted, use another library.

[PascalSchumacher]

This also affects writing Lists (at least in version 2.17.2). @gimiz Thank you very much for the workaround!

By the way: Thank you very much for developing/providing Jackson.