This causes 'nix' to print build log output to stderr rather than
showing the last log line in the progress bar. Log lines are prefixed
by the name of the derivation (minus the version string), e.g.
binutils> make[1]: Leaving directory '/build/binutils-2.31.1'
binutils-wrapper> unpacking sources
binutils-wrapper> patching sources
...
binutils-wrapper> Using dynamic linker: '/nix/store/kr51dlsj9v5cr4n8700jliyz8v5b2q7q-bootstrap-stage0-glibc/lib/ld-linux-x86-64.so.2'
bootstrap-stage2-gcc-wrapper> unpacking sources
...
linux-headers> unpacking sources
linux-headers> unpacking source archive /nix/store/8javli69jhj3bkql2c35gsj5vl91p382-linux-4.19.16.tar.xz
It was getting confused between logical and real store paths.
Also, make fetchGit and fetchMercurial update allowedPaths properly.
(Maybe the evaluator, rather than the caller of the evaluator, should
apply toRealPath(), but that's a bigger change.)
The value of useChroot is not set yet in the constructor, resulting in
hash rewriting being enabled in certain cases where it should not be.
Fixes#2801
For text files it is possible to do it like so:
`builtins.hashString "sha256" (builtins.readFile /tmp/a)`
but that doesn't work for binary files.
With builtins.hashFile any kind of file can be conveniently hashed.
To determine which seccomp filters to install, we were incorrectly
using settings.thisSystem, which doesn't denote the actual system when
--system is used.
Fixes#2791.
Thus
$ nix dev-shell
will now build the 'provides.devShell' attribute from the flake in the
current directory. If it doesn't exist, it falls back to
'provides.defaultPackage'.
'nix dev-shell' is intended to replace nix-shell. It supports flakes,
e.g.
$ nix dev-shell nixpkgs:hello
starts a bash shell providing an environment for building 'hello'.
Like Lorri (and unlike nix-shell), it computes the build environment
by building a modified top-level derivation that writes the
environment after running $stdenv/setup to $out and exits. This
provides some caching, so it's faster than nix-shell in some cases
(especially for packages with lots of dependencies, where the setup
script takes a long time).
There also is a command 'nix print-dev-env' that prints out shell code
for setting up the build environment in an existing shell, e.g.
$ . <(nix print-dev-env nixpkgs:hello)
https://github.com/tweag/nix/issues/21
