C++ nix uses C-style zero-terminated char pointers to represent strings internally - however, up to this point, tvix has used Rust `String` and `str` for string values. Since those are required to be valid utf-8, we haven't been able to properly represent all the string values that Nix supports. To fix that, this change converts the internal representation of the NixString struct from `Box<str>` to `BString`, from the `bstr` crate - this is a wrapper around a `Vec<u8>` with extra functions for treating that byte vector as a "morally string-like" value, which is basically exactly what we need. Since this changes a pretty fundamental assumption about a pretty core type, there are a *lot* of changes in a lot of places to make this work, but I've tried to keep the general philosophy and intent of most of the code in most places intact. Most notably, there's nothing that's been done to make the derivation stuff in //tvix/glue work with non-utf8 strings everywhere, instead opting to just convert to String/str when passing things into that - there *might* be something to be done there, but I don't know what the rules should be and I don't want to figure them out in this change. To deal with OS-native paths in a way that also works in WASM for tvixbolt, this also adds a dependency on the "os_str_bytes" crate. Fixes: b/189 Fixes: b/337 Change-Id: I5e6eb29c62f47dd91af954f5e12bfc3d186f5526 Reviewed-on: https://cl.tvl.fyi/c/depot/+/10200 Reviewed-by: tazjin <tazjin@tvl.su> Reviewed-by: flokli <flokli@flokli.de> Reviewed-by: sterni <sternenseemann@systemli.org> Autosubmit: aspen <root@gws.fyi> Tested-by: BuildkiteCI |
||
---|---|---|
.. | ||
.vscode | ||
boot | ||
build | ||
build-go | ||
castore | ||
castore-go | ||
cli | ||
docs | ||
eval | ||
glue | ||
nar-bridge | ||
nix-compat | ||
nix-lang-test-suite | ||
scripts | ||
serde | ||
store | ||
store-go | ||
tools | ||
verify-lang-tests | ||
website | ||
.gitignore | ||
buildkite.yml | ||
Cargo.lock | ||
Cargo.nix | ||
Cargo.toml | ||
clippy.toml | ||
crate-hashes.json | ||
default.nix | ||
LICENSE | ||
logo.webp | ||
OWNERS | ||
README.md | ||
shell.nix |

Tvix is a new implementation of the Nix language and package manager. See the announcement post for information about the background of this project.
Tvix is developed by TVL in our monorepo, the depot
, at
//tvix. Code reviews take place on Gerrit, bugs are
filed in our issue tracker.
For more information about Tvix, feel free to reach out. We are interested in people who would like to help us review designs, brainstorm and describe requirements that we may not yet have considered.
Most of the discussion around development happens on our IRC channel, which you can join in several ways documented on tvl.fyi, or on our mailing list.
Contributions to Tvix follow the TVL review flow and contribution guidelines.
WARNING: Tvix is not ready for use in production. None of our current APIs should be considered stable in any way.
WARNING: Any other instances of this project or repository are
josh
-mirrors. We do not accept code contributions or issues outside of
the tooling and communication methods outlined above.
Components
This folder contains the following components:
//tvix/castore
- subtree storage/transfer in a content-addressed fashion//tvix/cli
- preliminary REPL & CLI implementation for Tvix//tvix/eval
- an implementation of the Nix programming language//tvix/nar-bridge
nar-bridge-http
: A HTTP webserver providing a Nix HTTP Binary Cache interface in front of a tvix-store
//tvix/nix-compat
- a Rust library for compatibility with C++ Nix, features like encodings and hashing schemes and formats//tvix/serde
- a Rust library for using the Nix language for app configuration//tvix/store
- a "filesystem" linking Nix store paths and metadata with the content-addressed layer
Some additional folders with auxiliary things exist and can be explored at your leisure.
Building the CLI
The CLI can also be built with standard Rust tooling (i.e. cargo build
),
as long as you are in a shell with the right dependencies.
- If you cloned the full monorepo, it can be provided by
mg shell //tvix:shell
. - If you cloned the
tvix
workspace only (git clone https://code.tvl.fyi/depot.git:workspace=views/tvix.git
),nix-shell
provides it.
If you're in the TVL monorepo, you can also run mg build //tvix/cli
(or mg build
from inside that folder) for a more incremental build.
Please follow the depot-wide instructions on how to get mg
and use the depot
tooling.
Compatibility
Important note: We only use and test Nix builds of our software against Nix 2.3. There are a variety of bugs and subtle problems in newer Nix versions which we do not have the bandwidth to address, builds in newer Nix versions may or may not work.
Rust projects, crate2nix
Some parts of Tvix are written in Rust. To simplify the dependency
management on the Nix side of these builds, we use crate2nix
in a
single Rust workspace in //tvix
to maintain the Nix build
configuration.
When making changes to Cargo dependency configuration in any of the
Rust projects under //tvix
, be sure to run
mg run //tools:crate2nix-generate
in //tvix
itself and commit the changes
to the generated Cargo.nix
file. This only applies to the full TVL checkout.
License structure
All code implemented for Tvix is licensed under the GPL-3.0, with the exception of the protocol buffer definitions used for communication between services which are available under a more permissive license (MIT).
The idea behind this structure is that any direct usage of our code (e.g. linking to it, embedding the evaluator, etc.) will fall under the terms of the GPL3, but users are free to implement their own components speaking these protocols under the terms of the MIT license.