An old link still knows the way
The first post on this site is about a photo that disappeared from a 2012 blog entry while the link to it kept working. Link rot is the reason this engine exists, so an engine that quietly broke its own URLs would be a bad joke.
Renaming a post changes its address. That's unavoidable — the slug is the URL. What's avoidable is the old address turning into a 404.
What renaming does now
Rename a post — r in the properties dialog — and the post records its old address inside itself. The build then keeps a one-page redirect standing at every address the post has ever had.
The link in a two-year-old toot keeps resolving. The link somebody put in their own blog post keeps resolving. You get to fix a slug you regret without the fix costing you every reference to it that already exists in the world.
