A command like
$ nix run nixpkgs#hello
will now build the attribute 'packages.${system}.hello' rather than
'packages.hello'. Note that this does mean that the flake needs to
export an attribute for every system type it supports, and you can't
build on unsupported systems. So 'packages' typically looks like this:
packages = nixpkgs.lib.genAttrs ["x86_64-linux" "i686-linux"] (system: {
hello = ...;
});
The 'checks', 'defaultPackage', 'devShell', 'apps' and 'defaultApp'
outputs similarly are now attrsets that map system types to
derivations/apps. 'nix flake check' checks that the derivations for
all platforms evaluate correctly, but only builds the derivations in
'checks.${system}'.
Fixes#2861. (That issue also talks about access to ~/.config/nixpkgs
and --arg, but I think it's reasonable to say that flakes shouldn't
support those.)
The alternative to attribute selection is to pass the system type as
an argument to the flake's 'outputs' function, e.g. 'outputs = { self,
nixpkgs, system }: ...'. However, that approach would be at odds with
hermetic evaluation and make it impossible to enumerate the packages
provided by a flake.
Previously, SANDBOX_SHELL was set to empty when unavailable. This
caused issues when actually generating the sandbox. Instead, just set
SANDBOX_SHELL when --with-sandbox-shell= is non-empty. Alternative
implementation to https://github.com/NixOS/nix/pull/3038.
Pure mode should not try to source the user’s bashrc file. These may
have many impurities that the user does not expect to get into their
shell.
Fixes#3090
Fixes
$ nix build
fatal: bad revision 'HEAD'
error: program 'git' failed with exit code 128
on a new flake. It is now detected as a dirty tree with revCount = 0.
Only variables that were marked as exported are exported in the dev
shell. Also, we no longer try to parse the function section of the env
file, fixing
$ nix dev-shell
error: shell environment '/nix/store/h7ama3kahb8lypf4nvjx34z06g9ncw4h-nixops-1.7pre20190926.4c7acbb-env' has unexpected line '/^[a-z]?"""/ {'
For example, if the top-level flake depends on
"nixpkgs/release-19.03", and one of its dependencies depends on
"nixpkgs", then the latter will be mapped to "nixpkgs/release-19.03",
rather than whatever the default branch of "nixpkgs" is. Thus you get
only one "nixpkgs" dependency rather than two.
This currently only works in a breadth-first way, so the other way
around (i.e. if the top-level flake depends on "nixpkgs", and a
dependency depends on "nixpkgs/release-19.03") still results in two
"nixpkgs" dependencies.
If 'input.<name>.uri' changes, then the entry in the lockfile for
input <name> should be considered stale.
Also print some messages when lock file entries are added/updated.
This integrates the functionality of the index-debuginfo program in
nixos-channel-scripts to maintain an index of DWARF debuginfo files in
a format usable by dwarffs. Thus the debug info index is updated by
Hydra rather than by the channel mirroring script.
Example usage:
$ nix copy --to 'file:///tmp/binary-cache?index-debug-info=true' /nix/store/vr9mhcch3fljzzkjld3kvkggvpq38cva-nix-2.2.2-debug
$ cat /tmp/binary-cache/debuginfo/036b210b03bad75ab2d8fc80b7a146f98e7f1ecf.debug
{"archive":"../nar/0313h2kdhk4v73xna9ysiksp2v8xrsk5xsw79mmwr3rg7byb4ka8.nar.xz","member":"lib/debug/.build-id/03/6b210b03bad75ab2d8fc80b7a146f98e7f1ecf.debug"}
Fixes#3083.
So you now get
$ nix build
error: path '.' is not a flake (because it does not reference a Git repository)
rather than
$ nix build
error: unsupported argument '.'
Instead of a list, inputs are now an attrset like
inputs = {
nixpkgs.uri = github:NixOS/nixpkgs;
};
If 'uri' is omitted, than the flake is a lookup in the flake registry, e.g.
inputs = {
nixpkgs = {};
};
but in that case, you can also just omit the input altogether and
specify it as an argument to the 'outputs' function, as in
outputs = { self, nixpkgs }: ...
This also gets rid of 'nonFlakeInputs', which are now just a special
kind of input that have a 'flake = false' attribute, e.g.
inputs = {
someRepo = {
uri = github:example/repo;
flake = false;
};
};
Previously we allowed any length of name for Nix derivations. This is
bad because different file systems have different max lengths. To make
things predictable, I have picked a max. This was done by trying to
build this derivation:
derivation {
name = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
builder = "/no-such-path";
system = "x86_64-linux";
}
Take off one a and it will not lead to file name too long. That ends
up being 212 a’s. An even smaller max could be picked if we want to
support more file systems.
Working backwards, this is why:
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-${name}.drv.chroot
> 255 - 32 - 1 - 4 - 7 = 211
These are already handled separately. This fixes warnings like
warning: ignoring the user-specified setting 'max-jobs', because it is a restricted setting and you are not a trusted user
when using the -j flag.
If a NAR is already in the store, addToStore doesn't read the source
which makes the protocol go out of sync. This happens for example when
two client try to nix-copy-closure the same derivation at the same time.
Introduce the SizeSource which allows to bound how much data is being
read from a source. It also contains a drainAll() function to discard
the rest of the source, useful to keep the nix protocol in sync.
With this patch, and this file I called `log.py`:
#!/usr/bin/env nix-shell
#!nix-shell -i python3 -p python3 --pure
import sys
from pprint import pprint
stack = []
timestack = []
for line in open(sys.argv[1]):
components = line.strip().split(" ", 2)
if components[0] != "function-trace":
continue
direction = components[1]
components = components[2].rsplit(" ", 2)
loc = components[0]
_at = components[1]
time = int(components[2])
if direction == "entered":
stack.append(loc)
timestack.append(time)
elif direction == "exited":
dur = time - timestack.pop()
vst = ";".join(stack)
print(f"{vst} {dur}")
stack.pop()
and:
nix-instantiate --trace-function-calls -vvvv ../nixpkgs/pkgs/top-level/release.nix -A unstable > log.matthewbauer 2>&1
./log.py ./log.matthewbauer > log.matthewbauer.folded
flamegraph.pl --title matthewbauer-post-pr log.matthewbauer.folded > log.matthewbauer.folded.svg
I can make flame graphs like: http://gsc.io/log.matthewbauer.folded.svg
---
Includes test cases around function call failures and tryEval. Uses
RAII so the finish is always called at the end of the function.
Jonas Chevalier
