Co-authored-by: Robin Gloster <mail@glob.in>
stdenv: print message if structuredAttrs is enabled
stdenv: add _append
reduces the chance of a user doing it wrong
fix nix develop issue
output hooks don't work yet in nix develop though
making $outputs be the same on non-structuredAttrs and structuredAttrs
is too much trouble.
lets instead make a function that gets the output names
reading environment file '/nix/store/2x7m69a2sm2kh0r6v0q5s9z1dh41m4xf-xz-5.2.5-env-bin'
nix: src/nix/develop.cc:299: std::string Common::makeRcScript(nix::ref<nix::Store>, const BuildEnvironment&, const Path&): Assertion `outputs != buildEnvironment.vars.end()' failed.
use a function to get all output names instead of using $outputs
copy env functionality from https://github.com/NixOS/nixpkgs/pull/76732/commits
In specific cases, combining the `checkMeta` and `checkMetaRecursively`
config options would result in `error: infinite recursion encountered`
fixes#193296
This is needed in order to mark a certain derivation containing a Nix
expression tarball to Hydra so that it is recognised as a channel.
When I first got an evaluation error due to using this meta attribute, I
was under the impression that nobody outside of Vuizvui[1] is using this
feature and that we don't have any occurrence of isHydraChannel in
Nixpkgs.
However, when working around[2] the issue I assumed that it's not
something that should be included in Nixpkgs because we're not using it
there.
It turned out that my assumption was wrong and we *do* use the attribute
in Nixpkgs, namely via releaseTools.channel, which is similar to what
we're doing in Vuizvui.
Since we already include a bunch of undocumented attributes in
metaTypes, it only makes sense to add isHydraChannel as well since it's
actually documented in the Hydra documentation[3].
[1]: https://github.com/openlab-aux/vuizvui
[2]: https://github.com/openlab-aux/vuizvui/commit/e0685e81b3fdc43a272f0
[3]: 53335323ae/doc/manual/src/jobs.md (meta-fields)
Signed-off-by: aszlig <aszlig@nix.build>
Passing `-l$NIX_BUILD_CORES` improperly limits the overall system load.
For a build machine which is configured to run `$B` builds where each
build gets `total cores / B` cores (`$C`), passing `-l $C` to make will
improperly limit the load to `$C` instead of `$B * $C`.
This effect becomes quite pronounced on machines with 80 cores, with
40 simultaneous builds and a cores limit of 2. On a machine with this
configuration, Nix will run 40 builds and make will limit the overall
system load to approximately 2. A build machine with this many cores
can happily run with a load approaching 80.
A non-solution is to oversubscribe the machine, by picking a larger
`$C`. However, there is no way to divide the number of cores in a way
which fairly subdivides the available cores when `$B` is greater than
1.
There has been exploration of passing a jobserver in to the sandbox,
or sharing a jobserver between all the builds. This is one option, but
relatively complicated and only supports make. Lots of other software
uses its own implementation of `-j` and doesn't support either `-l` or
the Make jobserver.
For the case of an interactive user machine, the user should limit
overall system load using `$B`, `$C`, and optionally systemd's
cpu/network/io limiting features.
Making this change should significantly improve the utilization of our
build farm, and improve the throughput of Hydra.
inherit_errexit wasn’t available in bash 3. We have a check to show a
nice error message, but that check is after we set inherit_errexit in
setup.sh. So we can just move this to below the BASH_VERSINFO check.
the motivation for this is to simplify stdenv and ease the job of
reviewers due to them needing to tell contributors about the defacto
rule that mesonFlags should be a list of strings
the motivation for this is to simplify stdenv and ease the job of
reviewers due to them needing to tell contributors about the defacto
rule that cmakeFlags should be a list of strings
Closes#178625
The `busybox` version of `mktemp` requires exactly six `X` characters
in the argument to `mktemp`, unlike the `coreutils` version of `mktemp`.
Let's accomodate packages, like `epson-escpr2`, which fool `setup.sh`
into using the `busybox` version instead of the `stdenv` version.
it may be what the license handling code does, but it's confusing and not very useful
Co-authored-by: Adam Joseph <54836058+a-m-joseph@users.noreply.github.com>
libtool's libtool.m4 script assumes that `file` is available, and can
be found at `/usr/bin/file` (this path is hardwired). Furthermore,
the script with this assumption is vendored into the ./configure
scripts of an enormous number of packages. Without this commit, you
will frequently see errors like this during the configurePhase with
the sandbox enabled:
./configure: line 9595: /usr/bin/file: command not found
Due mostly to luck, this error does not affect native compiles on
nixpkgs' two most popular platforms, x86_64-linux and aarch64-linux.
However it will cause incorrect linker flag detection and a failure to
generate shared libraries for sandboxed cross-builds to a x86_64-linux
host as well as any sandboxed build (cross or native) for the following
hosts: x86_64-freebsd, *-hpux, *-irix, mips64*-linux, powerpc*-linux,
s390x-linux, s390x-tpf, sparc-linux, and *-solaris.
This commit fixes the problem by adding an extra line to fixLibtool()
in pkgs/stdenv/generic/setup.sh. This extra line will scan the
unpacked source code for executable files named "configure" which
contain the following text:
'GNU Libtool is free software; you can redistribute it and/or modify'
This text is taken to be an indicator of a vendored libtool.m4. When
it is found, the configure script containing it is subjected to `sed
-i s_/usr/bin/file_file_` which replaces all occurrences of
`/usr/bin/file` with `file`.
Additionally, the `file` package is now considered to be part of
`stdenv`. It has been added to `common-path.nix` so that the `file`
binary will be found in the `$PATH` of every build, except for the
bootstrap-tools and the first few stages of stdenv boostrapping.
Verified no regressions under:
nix-build --arg pkgs 'import ./. {}' ./lib/tests/release.nix
This commit allows the following commands to complete, which should
enable Hydra to produce bootstrap-files for mips64el:
nix-build \
--option sandbox true \
--option sandbox-fallback false \
pkgs/top-level/release-cross.nix \
-A bootstrapTools.mips64el-linux-gnuabi64.build
nix-build \
--option sandbox true \
--option sandbox-fallback false \
. \
-A pkgsCross.mips64el-linux-gnuabi64.nix_2_4
Instead of requiring the platforms be equal, use `isCompatible` to
determine if we can execute tests. The upside of this is that we now
can execute tests for natively cross compiled package sets like
pkgsStatic, pkgsLLVM and pkgsCross.musl64 etc.
the motivation for this is to simplify stdenv and ease the job of
reviewers due to them needing to tell contributors about the defacto
rule that configureFlags should be a list of strings
This warning logs when a package has no maintainers. It will stay silent
if `meta.maintainers` is not set at all, only complaining when it is an
empty list. In the future a separate warning could be added to allow for
that stricter behavior. Or this warning could be changed.
This will allow for adding more validity types in the future, such as a
warning type. (which is in the next commit in this series)
This is NOT a breaking change because validity.valid is never exposed
outside of `stdenv.mkDerivation`.
This isn't really desirable in general, but given that Nix itself
currently relies on this behaviour and that we don't want to break
backwards compatibility we should support it for now, maybe
deprecating it in the future.
This change is prompted by the following, admittedly cursed tarball:
```
> curl https://registry.npmjs.org/char-regex/-/char-regex-1.0.2.tgz 2>/dev/null \
| tar -ztv
drw-rw-rw- 0/0 0 2020-02-18 10:50 package
-rw-rw-rw- 0/0 297 2020-02-18 10:50 package/index.d.ts
-rw-rw-rw- 0/0 1920 2020-02-18 10:50 package/index.js
-rw-rw-rw- 0/0 1092 2020-01-31 11:31 package/LICENSE
-rw-rw-rw- 0/0 937 2020-02-18 10:51 package/package.json
-rw-rw-rw- 0/0 713 2020-02-18 10:50 package/README.md
```
The minimal reproducer for the issue is the following derivation trying
to work around the uid 0 issue with `dontMakeSourcesWritable = true`:
```nix
{ stdenv, fetchurl }:
stdenv.mkDerivation {
name = "test";
src = fetchurl {
sha1 = "d744358226217f981ed58f479b1d6bcc29545dcf";
url = "https://registry.npmjs.org/char-regex/-/char-regex-1.0.2.tgz";
};
dontMakeSourcesWritable = true;
installPhase = ''
cp -R . $out
'';
}
```
This currently fails in the following way:
```
these derivations will be built:
/nix/store/pc3jbydl0xcc8nrndf5xkf7hdhpgpb41-test.drv
building '/nix/store/pc3jbydl0xcc8nrndf5xkf7hdhpgpb41-test.drv'...
unpacking sources
unpacking source archive /nix/store/v9p98kqplf4kflmy91p0687xlvr6klb1-char-regex-1.0.2.tgz
source root is package
find: 'package/index.d.ts': Permission denied
find: 'package/index.js': Permission denied
find: 'package/LICENSE': Permission denied
find: 'package/package.json': Permission denied
find: 'package/README.md': Permission denied
/nix/store/6c47azxacncswc1pllzj28zfzqw40d7c-stdenv-linux/setup: line 1311: cd: package: Permission denied
builder for '/nix/store/pc3jbydl0xcc8nrndf5xkf7hdhpgpb41-test.drv' failed with exit code 1
error: build of '/nix/store/pc3jbydl0xcc8nrndf5xkf7hdhpgpb41-test.drv' failed
```
As you can see, the issue is that `$sourceRoot` isn't executable,
prohibiting the call to `cd`. This can be fixed by running
`chmod +x "${sourceRoot}"` before `cd` regardless of
`dontMakeSourcesWritable` in `unpackPhase` since if `chmod` fails, `cd`
would fail as well and we are out of options.
Verified that the workaround works locally.
Another thing to investigate is investigating if we should use
`--no-same-owner` for `tar` and if it helps in this case as well.
See also <https://github.com/Profpatsch/yarn2nix/issues/56>.
Flake users that use a command like `nix build nixpkgs#hello` on a
broken/insecure package will not be able to use an environment variable
to override that behavior, unless they pass `--impure` to the command.
Co-authored-by: pkharvey <kayharvey@protonmail.com>
Add `shellDryRun` to the generic stdenv and substitute it for uses of
`${stdenv.shell} -n`. The point of this layer of abstraction is to add
the flag `-O extglob`, which resolves#126344 in a more direct way.
Packages that use libtool run it as a wrapper around the linker.
Before calling the linker, libtool will determine what libraries would
be linked, and check if there's a corresponding libtool
archive (libfoo.la) file in the same directory . This file
contains extra information about the library. This is especially
important for static linking, because static archives don't contain
dependency information, so we need libtool to use the .la files to
figure out which libraries actually need to be linked against.
But in Nixpkgs, this has never worked. libtool isn't able to find any
libraries, because only the compiler wrapper knows how to find them,
and the compiler wrapper is opaque to libtool. This is why
pkgsStatic.util-linuxMinimal doesn't build prior to this patch — it
depends on libpam, which depends on libaudit, and if libtool can't
find the .la file, nothing will tell the linker to also link against
libaudit when linking libpam. (It was previously possible to build a
static util-linux, because linux-pam only recently had the audit
dependency added.)
There are a couple of ways we could fix this, so that libtool knows
where to look for .la files.
* Set LD_LIBRARY_PATH/DYLD_LIBRARY_PATH/whatever, which libtool will
examine. This would have major side effects though, because the
dynamic linker looks at it too.
* Inject libtool scripts with the appropriate information. That's
what I've done here. It was the obvious choice because we're
already finding and modifying the libtool scripts, to remove paths
outside the Nix store that libtool might check in unsandboxed
builds. Instead of emptying out the system paths, we can
repopulate it with our own library paths.
(We can't use a wrapper like we do for other tools in Nixpkgs, because
libtool scripts are often distributed in source tarballs, so we can't
just add a wrapped version of libtool as a dependency. That's why
there's already the fixLibtool function in stdenv.)
With this change, libtool is able to discover .la files, and
pkgsStatic.util-linuxMinimal can build again, linking correctly
against libpam and libaudit.
This reverts commit 488395c0f8.
Currently, `nix print-dev-env` fails to execute if this function is present, because of its use of hex literals.
Until this issue (https://github.com/NixOS/nix/issues/5262) is solved, we should revert this to prevent breakage.
somehow `read -N 0` behavior changed in bash 5. `read -d ''` has identical behavior
the purpose of the function is to read stdin and exit 1 on a null byte (i.e. if stdin is the content of a binary)
(cherry picked from commit 5d0acf20f8)
The old stdenv adapters were subtly wrong in two ways:
- `overrideAttrs` leaked the original, unoverridden `mkDerivation`.
- `stdenv.override` would throw away any manually-set `mkDerivation`
from a stdenv reverting to the original.
Now, `mkDerivation` is controlled (nearly directly) via an argument, and
always correctly closes over the final ("self") stdenv. This means the
adapters can work entirely via `.override` without any manual `stdenv //
...`, and both those issues are fixed.
Note hashes are changed, because stdenvs no previously overridden like
`stdenvNoCC` and `crossLibcStdenv` now are. I had to add some
`dontDisableStatic = true` accordingly. The flip side however is that
since the overrides compose, we no longer need to override anything but
the default `stdenv` from which all the others are created.
When we "fix" libtool, we empty out its system library path to avoid
it discovering libraries in e.g. /usr when the sandbox is disabled.
But this also means that the checks libtool does to make sure it can
find the libraries its supposed to be linking to won't work. On Linux
and Darwin, this isn't a problem, because libtool doesn't actually
perform any checks, but it is on at least NetBSD and Cygwin[1].
So, we force libtool not to do these checks on any platform, bringing
the more exotic platforms into line with the existing behaviour on
Linux and Darwin.
Without this change, lots of library packages produce warnings like
this in their build output on the platforms with checks by default:
*** Warning: linker path does not have real file for library -lz.
*** I have the capability to make that library automatically link in when
*** you link to this library. But I can only do this if you have a
*** shared version of the library, which you do not appear to have
*** because I did check the linker path looking for a file starting
*** with libz but no candidates were found. (...for regex pattern test)
*** The inter-library dependencies that have been dropped here will be
*** automatically added whenever a program is linked with this library
*** or is declared to -dlopen it.
And dependent packages break because libtool doesn't link their
transitive dependencies. So making this change fixes _lots_ of
packages on those platforms.
[1]: https://git.savannah.gnu.org/cgit/libtool.git/tree/m4/libtool.m4?id=544fc0e2c2a03129a540aebef41ad32bfb5c06b8#n3445
This confused the hell out of me, as I didn't spot the
> The following flags are disabled by default ...
when reading about `pie`, because that sentence was hidden in the
previous hardening flag's section.
Also explain that `pie` hardening is on by default on musl.
Only bash 4+ works in setup.sh. To make sure this is obvious, we can
check BASH_VERSINFO to get the major version number of Bash.
While Bash 3 is pretty rare, it still comes stock in macOS.
We *could* provide a warning here for non-Bash shells, but it’s not
always clear whether they will work or not. Zsh should have no trouble
while busybox sh, fish, or any others. There’s no great way to detect
what feature set the shell supports.
Fixes#71625
Patch every `derivation` call in the bootsrap process to add it a
conditional `__contentAddressed` parameter.
That way, passing `contentAddressedByDefault` means that the entire
build closure of a system can be content addressed
Adding the hostSuffix to the end of the derivation's name is problematic
since some stuff, including user facing programs like nix-env rely on
the behavior of parseDrvName instead of pname and version.
builtins.parseDrvName currently thinks that the cross compilation target
added via hostSuffix is part of the version. This has the practical
consequence for example that nix-env would think a cross compiled
derivation would be an updated version of a native derivation of the
same package and version — breaking user's profiles.
We can easily prevent this by moving the hostSuffix in between pname and
version. In case name is passed to mkDerivation this is of course not
possible and we are forced to fall back to the old behavior.
This change could serve as a replacement for the migitation we
introduced with the -static appendix to pname in order to avoid
confusion between nix and nixStatic as outlined in the comment added
with this commit.
Support `mainProgram` as an attribute of `meta` for packages.
This is an attribute used by [`nix
run`](https://nixos.org/manual/nix/unstable/command-ref/new-cli/nix3-run.html#description)
to customize the main program of a package.
For example, `pkgs.neovim` provides a `/bin/nvim` executable which users
would (almost certainly) prefer `nix run` to execute instead of a
non-existing `/bin/neovim`.
Signed-off-by: Ana Hobden <operator@hoverbear.org>
`hasCC` was getting overridden in the cross bootstrapping (for GHCJS),
which preventing the default logic from re-triggering for `stdenvNoCC`.
Also remove `stdenv.noCC` which is obseleted by `stdenv.hasCC`.
Add a config field `contentAddressedByDefault` and an associated
environment variable `NIXPKGS_CA_BY_DEFAULT` to make every nixpkgs
derivation content-addressed by default
This was removed in e29b0da9c7, because
it was felt it was ambiguous whether isBSD should remove Darwin.
I think it should be reintroduced. Packages sometimes have their own
concepts of "is BSD" e.g. Lua, and these almost never include Darwin,
so let's keep Darwin excluded.
Without a way to say "is this BSD", one has to list all flavours of
BSD seperately, even though fundamentally they're still extremely
similar. I don't want to have to write the following!
stdenv.isFreeBSD || stdenv.isNetBSD || stdenv.isOpenBSD || stdenv.isDragonFlyBSD
Additionally, we've had stdenv.hostPlatform.isBSD this whole time, and
it hasn't hurt anything.
Unify the logic for constructing the name from pname and version and
modifying the name in case a host suffix needs to appended. This allows
us to modify the construction of name from pname and version without
having to duplicate it in two places.
4e9dc46dea re-enabled hardening for Musl,
which is good.
Though static builds for ARM fail in various ways
- cross armv7l static does not build
- cross aarch64 static produces segfaulting dynamically linked binaries
- native aarch64 static also produces segfaulting dynamically linked binaries
It seems that for native x86_64-linux, static builds are fine though.
This works around the issue by removing PIE from the hardening flags,
keeping all other hardening flags. This is an improvement (I think) from
before 4e9dc46d.
Fixes#114953
* stdenv/check-meta: change to allowlist and blocklist
* Update pkgs/stdenv/generic/check-meta.nix
Co-authored-by: Graham Christensen <graham@grahamc.com>
Since the deprecation is fairly recent, we should warn by default.
Also fix the wording of the comment: stdenv.lib will be removed for the 21.11
release, not just deprecated (as it already is deprecated).
The `platform` field is pointless nesting: it's just stuff that happens
to be defined together, and that should be an implementation detail.
This instead makes `linux-kernel` and `gcc` top level fields in platform
configs. They join `rustc` there [all are optional], which was put there
and not in `platform` in anticipation of a change like this.
`linux-kernel.arch` in particular also becomes `linuxArch`, to match the
other `*Arch`es.
The next step after is this to combine the *specific* machines from
`lib.systems.platforms` with `lib.systems.examples`, keeping just the
"multiplatform" ones for defaulting.
By exporting it, we always make the new directories available
to subprocesses, regardless of whether the environment
variable existed before `nix-shell` was invoked.
This avoids the scenario where strictDeps is off and cross-compiled
XDG_DATA_DIRS content is brought into the environment.
While probably harmless for data like manpages and completion scripts,
this would cause issues when XDG_DATA_DIRS is used to find executables
or plugins. The Qt framework is known to behave like this and might
have run into incompatibilities.
XDG_DATA_DIRS is to /share as PATH is to /bin.
It was defined as part of the XDG basedir specification.
https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
While it originated from the X Desktop Group, it is not limited to
the X11 ecosystem, as evidenced by its use in bash-completion.
The removal of ` && -d "$pkg/bin"` is ok, because this optimization is
already performed by `addToSearchPath`.
This adds -frandom-seed to each compiler invocation in stdenv. The
object here is to make the compierl invocations produce the same output
every time they are called (for the same derivation). When the
-frandom-seed option is not set the compiler will use a combination of
random numbers (in GCC's case from /dev/urandom) and the durrent time to
produce a "random" input per file. This can (among other things) lead to
different ordering of symbols in the produced object files.
For reason of reproducibility we prefer having the same derivation
produce the exact same outputs. This is not a silver bullet but one way
to tame the compiler.
defaultHardeningFlags is set to enable pie for Musl, but is not
actually used because the default is never put into
NIX_HARDENING_ENABLE. That still works for cases other than Musl
only because NIX_HARDENING_ENABLE is defaulted in the binutils and
cc-wrapper setup-hook.sh scripts.
This hook moves systemd user service file from `lib/systemd/user` to
`share/systemd/user`. This is to allow systemd to find the user
services when installed into a user profile. The `lib/systemd/user`
path does not work since `lib` is not in `XDG_DATA_DIRS`.
This introduces the .inputDerivation attribute on all derivations
created with mkDerivation. This is another derivation that can always
build successfully and whose runtime dependencies are the build time
dependencies of the original derivation.
This allows easy building and distributing of all derivations needed to
enter a nix-shell with
nix-build shell.nix -A inputDerivation
I hate the thing too even though I made it, and rather just get rid of
it. But we can't do that yet. In the meantime, this brings us more
inline with autoconf and will make it slightly easier for me to write a
pkg-config wrapper, which we need.
The cross file is added in the `mkDerivation`. It isn't nice putting
build tool-specific stuff here, but our current architecture gives us
little alternative.
Currently it's not possible to determine the reason why a package is
unavailable without evaluating nixpkgs multiple times with different
settings. eg.
nix-repl> :p android-studio.meta
{ available = false; broken = false; unfree = true; unsupported = true; ... }
The following snippet is an example that uses this information to query
the availability information of all packages in nixpkgs, giving an
overview of all the packages currently marked as broken, etc.
{ pkgs }:
with import <nixpkgs/lib>;
let
mapPkgs =
let mapPkgs' = path: f: mapAttrs (n: v:
let result = builtins.tryEval (v ? meta); in
if !result.success then {} else
if isDerivation v then f (path ++ [n]) v else
if isAttrs v && v.recurseForDerivations or false then mapPkgs' (path ++ [n]) f v else
{}
);
in mapPkgs' [];
getMeta = path: drv:
if drv.meta ? available then
let meta = {
pkg = concatStringsSep "." path;
inherit (drv.meta) broken unfree unsupported insecure;
};
in builtins.trace meta.pkg meta
else {};
metaToList = attrs: flatten (map (v: if v ? pkg then v else metaToList v) (attrValues attrs));
in metaToList (mapPkgs getMeta pkgs)
While looking at the graph of all the outputs in my personal binary
cache it became obvious that we have a lot of self references within the
package set. That isn't an isuse by itself. However it increases the
size of the binary cache for every (reproducible) build of a package
that carries references to itself. You can no longer deduplicate the
outputs since they are all unique. One of the ways to get rid of (a few)
references is to rewrite all the symlinks that are currently used to be
relative symlinks. Two build of something that didn't really change but
carries a self-reference can the be store as the same NAR file again.
I quickly hacked together this change to see if that would yield and
success. My bash scripting skills are probably not great but so far it
seem to somewhat work.
Before, we'd always use `cc = null`, and check for that. The problem is
this breaks for cross compilation to platforms that don't support a C
compiler.
It's a very subtle issue. One might think there is no problem because we
have `stdenvNoCC`, and presumably one would only build derivations that
use that. The problem is that one still wants to use tools at build-time
that are themselves built with a C compiler, and those are gotten via
"splicing". The runtime version of those deps will explode, but the
build time / `buildPackages` versions of those deps will be fine, and
splicing attempts to work this by using `builtins.tryEval` to filter out
any broken "higher priority" packages (runtime is the default and
highest priority) so that both `foo` and `foo.nativeDrv` works.
However, `tryEval` only catches certain evaluation failures (e.g.
exceptions), and not arbitrary failures (such as `cc.attr` when `cc` is
null). This means `tryEval` fails to let us use our build time deps, and
everything comes apart.
The right solution is, as usually, to get rid of splicing. Or, baring
that, to make it so `foo` never works and one has to explicitly do
`foo.*`. But that is a much larger change, and certaily one unsuitable
to be backported to stable.
Given that, we instead make an exception-throwing `cc` attribute, and
create a `hasCC` attribute for those derivations which wish to
condtionally use a C compiler: instead of doing `stdenv.cc or null ==
null` or something similar, one does `stdenv.hasCC`. This allows quering
without "tripping" the exception, while also allowing `tryEval` to work.
No platform without a C compiler is yet wired up by default. That will
be done in a following commit.
Rewrite the `stripHash` helper function with 2 differences:
* Paths starting with `--` will no longer produce an error.
* Use Bash string manipulation instead of shelling out to `grep` and
`cut`. This should be faster.
A bunch of stdenv-internal variables were deleted in
1601a7fcce, but these are needed in the
fixup phase, whereas the rest are just needed for the initial work
(findInputs, etc) before the user phases.
CC @matthewbauer
There were two issues:
* builtins.getEnv was called deep into the nixpkgs tree making it hard
to discover. This is solved by moving the call into
pkgs/top-level/impure.nix
* when the config was explicitly set by the user to false, it would
still try and load the environment variable. This meant that it was
not possible to guarantee the same outcome on two different systems.
Before, we very carefully unapplied and reapplied `set -u` so the rest
of Nixpkgs could continue to not fail on undefined variables. Let's rip
off the band-aid.
A package's meta.license can either be a single license or a list. The
code to check config.whitelistedLicenses and config.blackListedLicenses
wasn't handling this, nor was the showLicense function.
These can be used to determine whether a ELF file with ELF header is an
executable or shared library.
We can't implement it in pure bash, as bash has problems with null
bytes.
That's very much consistent with the spirit of nix-shell --pure
BTW, nix 1.x shells will be always treated as pure;
in that version detection isn't possible.
https://github.com/NixOS/nix/commit/1bffd83e1a9c
