Postgresql: ArrayField with Unicode characters gets serialized as string of "\u XXXX" characters

[Oleg Sverdlov]

In ArrayField.value_to_string(self, obj) the value is encoded using JSON.dumps(values), which produces escaped Unicode \u XXXX by default.

For example, an ArrayField with 3 elements ["один", "два", "три"] (1,2,3 in Russian) will produce

["\u043e\u0434\u0438\u043d", "\u0434\u0432\u0430", "\u0442\u0440\u0438"]

While this is not a bug per se, this becomes a nuisance when viewing on result of "dumpdata" management command:

The ArrayField fields will be encoded differently from other text fields.

Perhaps there should be an option to turn on/off the ensure_ascii parameter in JSON.dumps(values, ensure_ascii=option)) ?

The option can be enabled by default, as we do for 'hstore' field, or perhaps enabled conditionally:

• in the field settings ArrayField(name='numbers', ascii_only=False)

• in settings.py ( ARRAY_FIELD_ENSURE_ASCII )

I will be glad to submit a patch.

[Simon Charette]

Given we made the decision to have JSON serialization default to ensure_ascii=False when dealing with Unicode in #29249 (68fc21b3784aa34c7ba5515ab02ef0c7b6ee856d) I think we should use the same approach here and use ensure_ascii=False for any usage of json.dumps in Field.value_to_string for fields that might include text which includes ArrayField, and HStoreField.

I don't think an additional field option to control this behavior and certainly not a setting is warranted here as it should be possible to subclass either field class to override value_to_string and ensure_ascii=False does constitute a more coherent default.