One line of colour
A reader changed one border colour in site.css, ran a rebuild, and waited while the build produced, byte for byte, every page that was already there. He asked why. The answer was one word in one list, and 1.7 takes it out.
What a build writes down
Since 1.6 the build keeps a record of what went into each page it wrote -- the post, the posts around it, the labels, the numbers a page counts. On the next build a page whose record has not moved is not rendered at all. Not rendered and then found identical: not rendered. The summary at the end says how many pages were left alone, the first number to look at when a build is slow.
The record holds only while the engine that wrote it is the same engine, so it hangs off a fingerprint of what the engine is made of -- the files under templates/, lib/, build/, locales/ and config/, hashed by contents rather than by timestamp. Change any of it and the record is discarded entire, because any of it can change every page.
