2daa483249
Update the tvix cli's -I option so that it aligns more closely with
nix's behavior: prepending entries to the list of lookup paths provided
by the NIX_PATH environment variable. Before this commit, using the -I
option would instead override and ignore the NIX_PATH variable.
Additionally, update the option's long name and help text to match the
new behavior.
While the tvix cli's interface does not appear to be attempting to mimic
nix exactly, I think this particular case of the -I option's diverging
behavior will inevitably surprise users because it's name, presumably
short for "include" and being similar to gcc's flag, evokes additivity.
The prior implementation hinted at this difference with the help text
and the long name, --nix-search-path, but I still suspect users will be
confused on first usage (at least I was). If we're willing to pay the
maintenance costs of additional code, we can avoid this and provide a
slightly smoother user experience.
Changes were tested by buiding the tvix cli, adding it to the PATH, and
executing simple tests as in the following bash script
mg build //tvix/cli
PATH="$PWD/result/bin:$PATH"
one=$(mktemp) && echo "=> $one :: path" > "$one"
two=$(mktemp) && echo "=> $two :: path" > "$two"
dir1=$(mktemp -d) && file1="$dir1/file1" && echo "=> $file1 :: path" > "$file1"
dir2=$(mktemp -d) && file2="$dir2/file2" && echo "=> $file2 :: path" > "$file2"
# NIX_PATH works with a single non-prefixed lookup path.
NIX_PATH="$dir1" tvix -E "<file1>" | cmp - "$file1"
# NIX_PATH works with multiple non-prefixed lookup paths.
NIX_PATH="$dir1:$dir2" tvix -E "<file2>" | cmp - "$file2"
# NIX_PATH works with a single prefixed lookup path.
NIX_PATH="one=$one" tvix -E "<one>" | cmp - "$one"
# NIX_PATH works with multiple prefixed lookup paths.
NIX_PATH="one=$one:two=$two" tvix -E "<one>" | cmp - "$one"
NIX_PATH="one=$one:two=$two" tvix -E "<two>" | cmp - "$two"
# NIX_PATH first entry takes precedence.
NIX_PATH="one=$one:one=$two" tvix -E "<one>" | cmp - "$one"
# The -I option works with a single non-prefixed lookup path.
tvix -I "$dir1" -E "<file1>" | cmp - "$file1"
# The -I option works with multiple non-prefixed lookup paths.
tvix -I "$dir1" -I "$dir2" -E "<file2>" | cmp - "$file2"
# The -I option works with a single prefixed lookup path.
tvix -I "one=$one" -E "<one>" | cmp - "$one"
# The --extra-nix-path option works with a single prefixed lookup path.
tvix --extra-nix-path "one=$one" -E "<one>" | cmp - "$one"
# The -I options works when passed multiple times with prefixed lookup paths.
tvix -I "one=$one" -I "two=$two" -E "<one>" | cmp - "$one"
tvix -I "one=$one" -I "two=$two" -E "<two>" | cmp - "$two"
# The first -I option takes precedence.
tvix -I "one=$one" -I "one=$two" -E "<one>" | cmp - "$one"
# Both NIX_PATH and the -I option work together and are additive.
NIX_PATH="one=$one" tvix -I "two=$two" -E "<one>" | cmp - "$one"
NIX_PATH="one=$one" tvix -I "two=$two" -E "<two>" | cmp - "$two"
# The -I option takes precedence over NIX_PATH.
NIX_PATH="one=$one" tvix -I "one=$two" -E "<one>" | cmp - "$two"
rm "$one"
rm "$two"
rm "$file1" && rmdir "$dir1"
rm "$file2" && rmdir "$dir2"
The above script assumes it's being run from inside the depot.
Change-Id: I153e6de57939c0eeca1f9e479d807862ab69b2de
Reviewed-on: https://cl.tvl.fyi/c/depot/+/13189
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
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||
|---|---|---|
| .. | ||
| .vscode | ||
| boot | ||
| build | ||
| build-go | ||
| castore | ||
| castore-go | ||
| cli | ||
| docs | ||
| eval | ||
| glue | ||
| nar-bridge | ||
| nix-compat | ||
| nix-compat-derive | ||
| nix-compat-derive-tests | ||
| nix-daemon | ||
| nix-lang-test-suite | ||
| scripts | ||
| serde | ||
| store | ||
| store-go | ||
| tracing | ||
| 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 | ||
| utils.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.
Development discussion is focused around two IRC channels, which are also available via XMPP and via Matrix.
-
TVL runs the
#tvlchannel on hackint. Tvix-related discussion in this channel is focused on eval, and on (almost) 1:1 replacements of C++ Nix with Rust components. -
The separate
#tvix-devchannel (on Matrix) focuses on the content-addressed store model, innovating on the plain files approach used in C++ Nix.
There is also a low-traffic mailing list with occasional design discussions.
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 methods outlined above.
Components
This folder contains the following components:
//tvix/boot- tooling to boot MicroVMs off oftvix-[ca]store//tvix/build- a generic (Nix-unaware) builder protocol and various implementations//tvix/castore- subtree storage/transfer in a content-addressed fashion//tvix/cli- preliminary REPL & CLI implementation for Tvix//tvix/docs- standalone documentation//tvix/eval- an implementation of the Nix programming language//tvix/glue- combines tvix-eval with tvix-[ca]store and tvix-build, implementation of build- and import-related builtins//tvix/nar-bridge- 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/nix-daemon- a Nix-compatible store daemon backed by Tvix//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//tvix/tracing- unified library to configure logging, tracing, instrumentation and progress concerns
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
tvixworkspace only (git clone https://code.tvl.fyi/depot.git:workspace=views/tvix.git),nix-shellprovides 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.
When adding/removing a Cargo feature for a crate, you will want to add it to the
features power set that gets tested in CI. For each crate there's a default.nix with a
mkFeaturePowerset invocation, modify the list to include/remove the feature.
Note that you don't want to add "collection" features, such as fs for tvix-[ca]store or default.
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.