I.e. do what git does. I'm too lazy to keep the builtin help text up
to date :-)
Also add ‘--help’ to various commands that lacked it
(e.g. nix-collect-garbage).
Channels are implemented using a profile now, and profiles contain a
manifest.nix file. This should be ignored to prevent bogus packages
from showing up in nix-env.
queryValidPaths() combines multiple calls to isValidPath() in one.
This matters when using the Nix daemon because it reduces latency.
For instance, on "nix-env -qas \*" it reduces execution time from 5.7s
to 4.7s (which is indistinguishable from the non-daemon case).
other simplifications.
* Use <nix/...> to locate the corepkgs. This allows them to be
overriden through $NIX_PATH.
* Use bash's pipefail option in the NAR builder so that we don't need
to create a temporary file.
This should also fix:
nix-instantiate: ./../boost/shared_ptr.hpp:254: T* boost::shared_ptr<T>::operator->() const [with T = nix::StoreAPI]: Assertion `px != 0' failed.
which was caused by hashDerivationModulo() calling the ‘store’
object (during store upgrades) before openStore() assigned it.
brackets, e.g.
import <nixpkgs/pkgs/lib>
are resolved by looking them up relative to the elements listed in
the search path. This allows us to get rid of hacks like
import "${builtins.getEnv "NIXPKGS_ALL"}/pkgs/lib"
The search path can be specified through the ‘-I’ command-line flag
and through the colon-separated ‘NIX_PATH’ environment variable,
e.g.,
$ nix-build -I /etc/nixos ...
If a file is not found in the search path, an error message is
lazily thrown.
checked too soon whether substitutes are available. That is, it did
so for every available package, rather than those matching installed
packages. This was very slow and subject to assertion failures. So
do the check much later. Idem for `nix-env -qab' and `nix-env -ib'.
a pointer to a Value, rather than the Value directly. This improves
the effectiveness of garbage collection a lot: if the Value is
stored inside the set directly, then any live pointer to the Value
causes all other attributes in the set to be live as well.
instance) "nix-env -i wine" works on x86_64-linux, even though Wine
is built on i686-linux. In the event that there are multiple
matching derivations, prefer those built for the current system.
errors with position info.
* For all positions, use the position of the first character of the
first token, rather than the last character of the first token plus
one.
