> An incremental rebuild will still be O(n), but in this case n=1. TFA explains pretty clearly what claim is being made. They're talking about the cost of rebu

> An incremental rebuild will still be O(n), but in this case n=1. TFA explains pretty clearly what claim is being made. They're talking about the cost of rebuilding one file, given the "input" of a project with n files. They claim that for other build systems that cost (the cost of one file) scales linearly with total project size, but for theirs it doesn't. Your objection here redefines n to be the number of files changed, but they don't claim anything about that.