On Tue, Jun 2, 2015 at 7:20 PM, Carter Schonwald
could you share a minimal program that reproduces the problem?
That's the thing, it's a thousand line shakefile that builds a 100k line program, and it's happening only rarely now. Since it happens so rarely it seems really difficult to prune away bits to see if it still happens. I suppose since the building is all just running commands, the source it's building doesn't matter, but since it's a build, it runs a different sequence of commands every time. I suppose I could "stub out" the program by replacing ghc with a shell script that sleeps and touches the output files, but it feels like I could spend days on it because there are tons of little details. I'm pretty sure it's related to the threaded runtime, because it doesn't happen without -threaded. I could try with -debug, but that probably turns off -threaded too, so no more problem. Shake is heavily threaded and nondeterministic. I haven't seen other shake users report it though.