Eelco Dolstra
4f09ce7940
This was caused by derivations with 'allowSubstitutes = false'. Such derivations will be built locally. However, if there is another SubstitionGoal that has the output of the first derivation in its closure, then the path will be simultaneously built and substituted. There was a check to catch this situation (via pathIsLockedByMe()), but it no longer worked reliably because substitutions are now done in another thread. (Thus the comment 'It can't happen between here and the lockPaths() call below because we're not allowing multi-threading' was no longer valid.) The fix is to handle the path already being locked in both SubstitutionGoal and DerivationGoal.
Nix, the purely functional package manager
Nix is a new take on package management that is fairly unique. Because of its purity aspects, a lot of issues found in traditional package managers don't appear with Nix.
To find out more about the tool, usage and installation instructions, please read the manual, which is available on the Nix website at http://nixos.org/nix/manual.
Contributing
Take a look at the Hacking Section of the manual. It helps you to get started with building Nix from source.
License
Nix is released under the LGPL v2.1
This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit.