Last modified: 2014-11-14 09:32:48 UTC
Several of our API modules use system messages to generate self-documentation, especially in the getPossibleErrors method. However, by convention, the API self-documentation should be english only. Consequently, all these messages are currently marked as DO NOT TRANSLATE in the qqq.json file. So, using messages there is pointless and misleading. The messages used in getPossibleErrors correspond to API error codes, and could be used for localizing errors reported using the dieError() or dieException() methods (see bug 64874). To do this, replace the message access in getPossibleErrors with a literal string, remove the DO NOT TRANSLATE marker in the qqq.json file, and replace calls to dieUsage with dieError or dieException, respectively.
I disagree that "the API self-documentation should be english only". It should be translatable, and the translations should be shown at [[Special:ApiSandbox]] (Bug 67950).
@Helder: the current consensus is that API error messages and self-documentation is english only. If you want to change this, please make an RDF for mediawiki core. This bug is making Wikibase compliant with the conventions defined for core.
possible errors were removed with Gerrit change #152760 from core