As of January 23rd, 2016, the development repository for Lucene and Solr has 
moved to a GIT (see issue LUCENE-6937).

The GIT repository contains full history of both projects
and can be found here:

git://git.apache.org/lucene-solr.git

The historical content of SVN repository is preserved. If you wish 
to see the last revision before the migration, use:

svn update -r 1726343