Pjotr Prins <[email protected]> skribis: > On Thu, Jan 21, 2016 at 09:50:18AM +0100, Ludovic Courtès wrote: >> This is expected: origins are fixed-output derivations, meaning that it >> does not matter how we perform them (using Git, over HTTP, or thanks to >> an avian carrier), as long as the result has the specified sha256. >> >> Thus, when you change, say, the Git commit ID or origin ‘method’ without >> changing the ‘sha256’ field, nothing happens: the daemon says “OK, I >> already have a store item with that ‘sha256’, so I don’t do anything.” >> >> Clearly, one has to be cautious with this, it’s easy to mistakenly use >> the old source. > > Hmmm. I thought the sha256 was calculated over the derivation + > sources
What you’re saying is true of the hash that appears in /gnu/store file name, but I was referring to the ‘sha256’ field of origins, which is a different thing. Ludo’.
