On 04.02.2016 18:59, Daniel Kinzler wrote:
Am 04.02.2016 um 08:03 schrieb Markus Krötzsch:
Data model updates are costly. Don't make them on a week's notice, without prior discussion, and without having any documentation ready to give to data users. It would also be good to announce breaking technical changes more prominently on wikidata-tech as well.
These have been discussed for months, if not years. Especially identifiers.
Citation needed ;-) Note that my emails were about math, not about the identifiers. Also, discussing about something is not enough. In the end, you need to give us the technical details so we can fix our tools. I knew that you planned to introduce identifier types, but I still don't know the RDF IRI for this new type.
I do not consider adding new data types a breaking change. Converting existing properties to a different data type is a breaking change to the data-set, not to the model or the software.
No, sorry, this is just wrong. The datatypes are part of the model, not of the data. Changing the format of JSON to include new, hitherto unknown types might break a tool (and not break others). It will depend on the function of the tool (and its implementation technique) but some will break.
For example, a tool that converts Wikidata to RDF will have a problem if it encounters something that it cannot translate. This is hard to recover from, since you cannot even declare the exported property as a property at all unless you probe your data to find hints in the form of values that use this data (I don't think any existing export tool would work like this). As a result, you fail to export a significant part of the property definitions, which makes the dumps invalid for OWL, or you have to omit big parts of the data. This is clearly breaking essential functionality.
An earlier email in this thread reported that the recent changes also break pywikibot, but maybe this was another part of the changes and the one-week time-to-update I complain about does not apply there (maybe this break was clear earlier so the team there had more time to adjust?).
You really need to give people more time to accommodate data model changes -- and you should start counting the time when you have finished and publicised the documentation of a change. I can't believe that my question on the type IDs in JSON and RDF is still unanswered. I would really like to release an update of our software and online tools next week, so it would be good to know by then. Does nobody know this yet, or do you not have enough resources to say it, or what is the problem? We are no longer in those early years where everything was new and there were no applications to break.
Markus