4a058a9c00
Previously, the VM assumed that if an error was returned from `run()`, the evaluation was "finished" and the state of the VM didn't matter. This used to be a reasonable assumption, but now that we've got `tryEval` around we need to actually make sure that we clean up after ourselves if we're about to return an error. Specifically, if the *last* instruction in an evaluation frame returns an error, we previously wouldn't pop that evaluation frame, which could cause all sorts of bizarre errors based on what happened to be in the stack at the time. This commit splits out a `run_op` method from `VM::run`, and uses that to check the evaluation frame return condition even if the op we're running is about to return an error, and pop the evaluation frame if we're at the last instruction. Change-Id: Ib40649d8915ee1571153cb71e3d76492542fc3d7 Reviewed-on: https://cl.tvl.fyi/c/depot/+/6940 Tested-by: BuildkiteCI Reviewed-by: tazjin <tazjin@tvl.su> |
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| .. | ||
| benches | ||
| docs | ||
| proptest-regressions/value | ||
| src | ||
| tests | ||
| .envrc | ||
| .gitignore | ||
| .skip-subtree | ||
| Cargo.lock | ||
| Cargo.toml | ||
| default.nix | ||
| README.md | ||
| shell.nix | ||
Tvix Evaluator
This project implements an interpreter for the Nix programming language. You can experiment with an online version of the evaluator: tvixbolt.
The interpreter aims to be compatible with nixpkgs, on the
foundation of Nix 2.3.
Important note: The evaluator is not yet feature-complete, and while the core mechanisms (compiler, runtime, ...) have stabilised somewhat, a lot of components are still changing rapidly.
Please contact TVL with any questions you might have.
Building the evaluator
If you are in a full checkout of the TVL depot, you can simply run mg build in this directory (or mg build //tvix/eval from anywhere in
the repo).
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.
The evaluator can also be built with standard Rust tooling (i.e.
cargo build).
If you would like to clone only the evaluator and build it directly with Rust tooling, you can do:
git clone https://code.tvl.fyi/depot.git:/tvix/eval.git tvix-eval
cd tvix-eval && cargo build
Nix test suite
C++ Nix implements a language test suite in the form of Nix source code files, and their expected output. The coverage of this test suite is not complete, but we intend to be compatible with it.
We have ported the test suite to Tvix, but do not run it by default as we are not yet compatible with it.
You can run the test suite by enabling the nix_tests feature in
Cargo:
cargo test --features nix_tests
rnix-parser
Tvix is written in memory of jD91mZM2, the author of rnix-parser who sadly passed away.
Tvix makes heavy use of rnix-parser in its bytecode compiler. The parser is now maintained by Nix community members.