Ref T7664. The current algorithm for moving task subpriorities can end up stuck in a real sticky swamp in some unusual situations.
Instead, use an algorithm which works like this:
- When we notice two tasks are too close together, look at the area around those tasks (just a few paces).
- If things look pretty empty, we can just spread the tasks out a little bit.
- But, if things are still real crowded, take another look further.
- Keep doing that until we're looking at a real nice big spot which doesn't have too many tasks in it in total, even if they're all in one place right now.
- Then, move 'em out!
- Just swallow our pride and do the gross INSERT INTO ... "", "", "", "", "", "", ... ON DUPLICATE KEY UPDATE to bulk update.
- Fix an issue where a single move could cause two different subpriority recalculations.