Recently, in commit 5aee3bca6f, the db:delete and solr:nuke tasks were added to the depends on frontend:clean. It looks like this is in service to testing tasks around the frontend. However, frontend:clean ALSO gets run before frontend:devserver, so with this change, every time the devserver is run, the solr index and Derby demo DB are wiped.
I think this is a significant impediment to development, and it's surprised several devs over here.
Suggested fix: move the solr and db clears to either a separate task that is then included instead/in addition to frontend:clean where needed, or directly include the solr/db clears where needed.
This applies to all platforms, on points forward 5aee3bca6f on master (which is post 2.7.0)
It does not wipe MySQL/MariaDB db, just Derby, so people using MySQL or MariaDB will only lose Solr index.