Implement UnDeserializableValue::newFromJSON and toJSON

[filbertkm]

made the error attribute of the value be a string, with the error reason, for more consistency with the backend implementation and for better ease of use.

also fixed more of the wording and variable names from "ununserializable" to "undeserializable", for consistency purposes.

Bug: T99231

[thiemowmde]

If you want we can merge this and fix the tiny issues later. Please tell me.

[filbertkm]

I think we need to go back to the way I ordered the params before. UnDeserializableValue inherits from dv.DataValue which has a specific order. I think it's best to be consistent with that, even if it's different that in php.

[thiemowmde]

What do you mean with "specific order [in] dv.DataValue"?

[filbertkm]

@thiemowmde suppose the order doesn't totally matter, but in SnakDeserializer we have:

this.newDataValue = function( dataValueType, data )

it is independent though from the order we order the params here, and suppose we could change. i just prefer the order to be same as there.

[thiemowmde]

For reference:

• Agree on the order. SnakSerializer.js also uses type, value.
• I would feel a little bit better if the keys are the same as in UnDeserializableValue.php: type, value, error. But this is no reason to block this, since these names are not going anywhere if I'm correct.

[filbertkm]

gone back again and made the order "value, type, error" throughout the value class and am adjusting the SnakSerializer. ( i really don't care, but suppose it's consistent with php is a good reason)

[filbertkm]

and squashed the commits

[thiemowmde]

Thanks. +2 when the tests succeed.

[filbertkm]

https://phabricator.wikimedia.org/T100985

[filbertkm]

https://phabricator.wikimedia.org/T96892 is the correct task