Also, presumably builds will have to have write access to the cache, which means a malicious build can break things for other builds.
> On Dec 9, 2014, at 5:57 PM, Wout Mertens <[email protected]> wrote: > > I don't follow. It's a cache, so it always returns the same output for a > given set of inputs (compiler version, source files, preprocessor settings). > Its presence should be undetectable. > > The only impurity is that time taken to compile is dependent on previous > compiles, no? > > However, it is still useful for development but not if using it means > rebuilding the world on your laptop... So I'd like to at least offer the > option for development. > > Wout. > > On Tue Dec 09 2014 at 6:32:04 PM Shea Levy <[email protected] > <mailto:[email protected]>> wrote: > ccache is impure and thus should not be used for hydra. > > >> On Dec 9, 2014, at 5:28 PM, Wout Mertens <[email protected] >> <mailto:[email protected]>> wrote: >> > >> Hi all, >> >> there is some support for ccache in the tree but nothing in the way of >> documentation. I gave it a shot, see >> https://github.com/NixOS/nixpkgs/issues/2387#issuecomment-66215017 >> <https://github.com/NixOS/nixpkgs/issues/2387#issuecomment-66215017>, and it >> seems to work however it also changes the hash of stdenv. >> >> Is there a way to change stdenv so that ccache can be turned on or off >> without causing rebuilds? >> >> I'm convinced that this would be a major boon for Hydra, which probably >> spends a lot of time compiling the same C/C++ files with the same >> preprocessed output. Likewise for developing expressions. >> >> Wout. > >> _______________________________________________ >> nix-dev mailing list >> [email protected] <mailto:[email protected]> >> http://lists.science.uu.nl/mailman/listinfo/nix-dev >> <http://lists.science.uu.nl/mailman/listinfo/nix-dev> >
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