JSON lists not working correctly

[christian-thiele]

When querying a table with a jsonb column that contains a json list, the result is parsed correctly.
When trying to insert or update with the same list (the exact object that i received as result) I get this error:

PostgreSQLSeverity.error : Could not infer array type of value '[{key1: 123, key2: 456}]'.

I think the cause of this error is that the PostgresTextEncoder does not recognize the list as a JSON value:

if (value is Map) {
  return _encodeJSON(value, escapeStrings);
}

if (value is PgPoint) {
  return _encodePoint(value);
}

if (value is List) {
  return _encodeList(value);
}

(from text_codec.dart line 31 and following)

Also, there could be a bug in the _encodeList method here:

final type = value.fold(value.first.runtimeType, (type, item) {
  if (type == item.runtimeType) {
    return type;
  } else if ((type == int || type == double) && item is num) {
    return double;
  } else {
    return Map;
  }
});

(text_codec.dart line 176)

AFAIK comparing runtimeType is not advisable because (like in this scenario) it would result in type being _InternalLinkedHashMap<String, dynamic>. This would then clash with line 197 where type is compared to Map
but _InternalLinkedHashMap<String, dynamic> != Map. But since the syntax of the resulting sql would not fit for use with jsonb anyway, i think the first code part above is the root of my problem.

If you can give me some opinion about how this should be handled, i would be happy to contribute a PR for this.

Best regards