broken, but now the evaluator checks for it to prevent Nix
expressions from relying on undefined behaviour. Equality tests are
implemented using a shallow pointer equality test between ATerms.
However, because attribute sets are lazy and contain position
information, this can give false positives. For instance,
previously
let y = {x = 1;}; in y == y
evaluated to true, while the equivalent expression
{x = 1;} == {x = 1;}
evaluated to false. So disallow these tests for now. (Eventually
we may want to implement deep equality tests for attribute sets,
like lib.eqStrict.)
* Idem: disallow comparisons between functions.
* Implemented deep comparisons of lists. This had the same problem as
attribute sets - the elements in the list weren't evaluated. For
instance,
["xy"] == [("x" + "y")]
evaluated to false. Now it works properly.
(that is, call the build hook with a certain interval until it
accepts the build).
* build-remote.pl was totally broken: for all system types other than
the local system type, it would send all builds to the *first*
machine of the appropriate type.
poll for it (i.e. if we can't acquire the lock, then let the main
select() loop wait for at most a few seconds and then try again).
This improves parallelism: if two nix-store processes are both
trying to build a path at the same time, the second one shouldn't
block; it should first see if it can build other goals. Also, it
prevents the deadlocks that have been occuring in Hydra lately,
where a process waits for a lock held by another process that's
waiting for a lock held by the first.
The downside is that polling isn't really elegant, but POSIX doesn't
provide a way to wait for locks in a select() loop. The only
solution would be to spawn a thread for each lock to do a blocking
fcntl() and then signal the main thread, but that would require
pthreads.
would just silently store only (fileSize % 2^32) bytes.
* Use posix_fallocate if available when unpacking archives.
* Provide a better error message when trying to unpack something that
isn't a NAR archive.
