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jade 1eef1927b6 libexpr: fix accessing uninitialized values and fix pure-eval docs
We got UBSan working on Lix, so we of course immediately found a bug and
some definitely nonsense behaviour.

Accessing `pureEval` or `restrictEval` from a default setting value is
nonsense, since they would never be actually set by the time that value
is set so they are not going to do anything. The configuration is not
applied in an initializer (and even if it were, it's not going to be in
the right order).

After looking into *that*, we hunted down what actually was applying
these, since clearly this code did not do anything. The EvalState
constructor should have a "search path added and removed here :)" sign
on it, because that's where it is done. We added an explicit
initialization of the optional in there because it was otherwise unclear
why pureEval also has the search path to allowed paths setup code run.

We then realized that the `pureEval` documentation was *also* bogus, and
we rewrote it. In so doing, we realized that we forgot to file a bug to
make `builtins.storePath` work in pure eval mode, so we filed one of
those: lix-project/lix#402

Yaks have been thoroughly shorn.

UBSan report:

    ../src/libexpr/eval-settings.cc:66:10: runtime error: member call on address 0x752fa9a13060 which does not point to an object of type 'nix::BaseSetting<b
    ool>'
    0x752fa9a13060: note: object has invalid vptr
     00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00
                  ^~~~~~~~~~~~~~~~~~~~~~~
                  invalid vptr
        0 0x752fa95106a6 in nix::EvalSettings::getDefaultNixPath[abi:cxx11]() /home/jade/lix/lix2/build/src/libexpr/eval-settings.cc:66:10
        1 0x752fa950e420 in nix::EvalSettings::EvalSettings() /home/jade/lix/lix2/build/src/libexpr/eval-settings.hh:36:15
        2 0x752fa9469f1f in __cxx_global_var_init.50 /home/jade/lix/lix2/build/src/libexpr/eval-settings.cc:98:14
        3 0x752fa9469f1f in _GLOBAL__sub_I_eval_settings.cc /home/jade/lix/lix2/build/src/libexpr/eval-settings.cc
        4 0x752fabbd308d in call_init (/nix/store/k7zgvzp2r31zkg9xqgjim7mbknryv6bs-glibc-2.39-52/lib/ld-linux-x86-64.so.2+0x508d) (BuildId: a5b8228edc9f16078ac3c894af964eeb990ecb4c)
        5 0x752fabbd317b in _dl_init (/nix/store/k7zgvzp2r31zkg9xqgjim7mbknryv6bs-glibc-2.39-52/lib/ld-linux-x86-64.so.2+0x517b) (BuildId: a5b8228edc9f16078ac3c894af964eeb990ecb4c)
        6 0x752fabbe9c2f in _dl_start_user (/nix/store/k7zgvzp2r31zkg9xqgjim7mbknryv6bs-glibc-2.39-52/lib/ld-linux-x86-64.so.2+0x1bc2f) (BuildId: a5b8228edc9f16078ac3c894af964eeb990ecb4c)

Change-Id: I5d8ffb7bfbe24b6584020ac74eed93d9f2e6d111
2024-06-18 19:25:35 -07:00
.github .github: clean up stale things and wrong references 2024-06-12 15:34:23 -07:00
bench Add benchmarking scripts 2024-04-08 19:50:24 -07:00
clang-tidy clang-tidy: work with angle brackets and external projects 2024-05-24 02:22:58 +00:00
contrib function-trace: always show the trace 2019-09-18 23:23:21 +02:00
doc repl: implement tab completing :colon commands 2024-06-17 13:08:02 +00:00
lix-doc lix-doc: don't chomp bold headings off 2024-05-15 15:24:03 -07:00
maintainers releng: automatically add to the summary page 2024-06-15 18:46:18 -07:00
meson packaging: rename nixexpr -> lixexpr and so on 2024-05-23 16:45:23 -06:00
misc Misc workaround removals since 24.05 upgrade 2024-06-12 15:34:23 -07:00
nix-support Move version to a JSON file so we can have release names 2024-06-06 15:08:12 -07:00
perl Move version to a JSON file so we can have release names 2024-06-06 15:08:12 -07:00
releng releng: fix broken manifest from 2.90-rc1 2024-06-16 13:34:04 -07:00
scripts remove the autoconf+Make buildsystem 2024-05-07 17:04:30 -06:00
src libexpr: fix accessing uninitialized values and fix pure-eval docs 2024-06-18 19:25:35 -07:00
subprojects/aws_sdk build: fix static aws-cpp-sdk 2024-05-30 00:40:25 -06:00
tests filetransfer: {up,down}load -> transfer 2024-06-18 23:58:25 +00:00
.clang-format Add pre-commit checks 2024-03-29 22:57:40 -07:00
.clang-tidy Add basic clang-tidy config 2024-03-29 20:26:38 -07:00
.dir-locals.el .dir-locals.el: Set c-block-comment-prefix 2020-07-10 11:21:06 +02:00
.editorconfig add editorconfig for markdown 2024-05-24 02:22:44 +00:00
.envrc Set MAKEFLAGS=-j and GTEST_BRIEF in .envrc 2024-03-28 18:17:28 -07:00
.gitignore Put into place initial release engineering 2024-06-06 20:53:08 -07:00
boehmgc-coroutine-sp-fallback.diff [resubmit] flake: update nixpkgs pin 23.11->24.05 (+ boehmgc compat changes) 2024-06-12 15:34:22 -07:00
CONTRIBUTING.md chore: re-work the contribution guide 2024-05-07 01:28:35 +00:00
COPYING Add pre-commit checks 2024-03-29 22:57:40 -07:00
default.nix Format Nix code with nixfmt 2024-04-08 13:00:00 -07:00
docker.nix releng: support multiarch docker images 2024-06-09 20:33:24 -07:00
flake.lock [resubmit] flake: update nixpkgs pin 23.11->24.05 (+ boehmgc compat changes) 2024-06-12 15:34:22 -07:00
flake.nix Merge pull request #10799 from hercules-ci/safer-tab-completion 2024-06-16 04:03:32 +00:00
justfile justfile: remove --quiet from just test 2024-05-24 02:22:25 +00:00
meson.build s3: delete obsolete ifdefs 2024-06-18 15:11:49 -07:00
meson.options build: expose option to enable or disable precompiled std headers 2024-06-06 12:46:26 -06:00
package.nix packaging: Move binaryTarball to a passthru attr in package.nix 2024-06-13 15:14:22 -07:00
README.md chore: rebrand Nix to Lix when it makes sense 2024-06-01 20:31:24 +02:00
shell.nix shell.nix: conform to documentation 2024-05-27 16:47:40 +02:00
treefmt.toml Format Nix code with nixfmt 2024-04-08 13:00:00 -07:00
version.json version: update to 2.91-dev for main 2024-06-15 18:46:18 -07:00

Lix

Lix is an implementation of Nix, a powerful package management system for Linux and other Unix systems that makes package management reliable and reproducible.

Read more about us at https://lix.systems.

Installation

On Linux and macOS the easiest way to install Lix is to run the following shell command (as a user other than root):

$ curl -sSf -L https://install.lix.systems/lix | sh -s -- install

For systems that already have a Nix implementation installed, such as NixOS systems, read our install page

Building And Developing

See our Hacking guide in our manual for instruction on how to to set up a development environment and build Lix from source.

Additional Resources

License

Lix is released under the LGPL v2.1.