On 09/11/2010 19:08, Aryeh Gregor wrote:
On Mon, Nov 8, 2010 at 7:17 AM, Markus Krötzsch markus@semantic-mediawiki.org wrote:
The proposed backward compatibility page says that trunk extensions are only compatible with the current MW version. This implies that it is not possible to cleanly develop an extension that supports multiple MW versions in trunk at all: since branches are copies of an earlier state of the trunk, the proposed guidelines entail that branches are also compatible with only one version of MediaWiki.
Actually, what it says is:
"Extensions are branched along with MediaWiki, so trunk extensions only have to support current trunk MediaWiki. However, per #General principles, don't break support for old MediaWiki versions unless the compatibility code is causing actual quantifiable problems, because it's nice if users can get the extra features or bug fixes of trunk extensions even if they're still using old MediaWiki. Some extensions' maintainers deliberately maintain compatibility with old MediaWiki versions, and their wishes should be respected in all cases."
The last sentence answers your question. The phrase "have to" in the first sentence means they don't have to support old releases, but they can if their maintainers want them to.
Great, I overlooked this last part. +1 from me.
What remains of my email is the question how this "wish" is implemented technically. Either one has to generally give up potentially problematic updates on ./trunk/extensions, or there must be some record of each extension's compatibility wish to determine which extensions an update should be applied to.
-- Markus