feat(tvix/glue): Init fetcher builtins r/7557

Initialize a new empty builtins module `fetcher_builtins`, which will
contain the builtins which fetch URLs from the internet:

* fetchurl
* fetchGit
* fetchTarball
* fetchTree (maybe? this is experimental)

These builtins are all implemented in CPP nix at:
https://github.com/NixOS/nix/blob/2.20.2/src/libexpr/primops/fetchTree.cc

These builtins are added to the evaluation context using a similar
mechanism to the derivation builtins, and have been added everywhere
derivation builtins were previously being added.

Change-Id: I133b91cc9560f23028621414537f712e7bd8a825
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10974
Autosubmit: aspen <root@gws.fyi>
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

1 files changed, 15 insertions, 3 deletions

diff --git a/tvix/glue/src/builtins/mod.rs b/tvix/glue/src/builtins/mod.rs
index dff6a8947c16..4a59ec9ea6e5 100644
--- a/tvix/glue/src/builtins/mod.rs
+++ b/tvix/glue/src/builtins/mod.rs
@@ -6,6 +6,7 @@ use crate::tvix_store_io::TvixStoreIO;
 
 mod derivation;
 mod derivation_error;
+mod fetchers;
 
 pub use derivation_error::Error as DerivationError;
 
@@ -17,20 +18,30 @@ pub use derivation_error::Error as DerivationError;
 /// `known_paths`.
 pub fn add_derivation_builtins<IO>(eval: &mut tvix_eval::Evaluation<IO>, io: Rc<TvixStoreIO>) {
     eval.builtins
-        .extend(derivation::derivation_builtins::builtins(io));
+        .extend(derivation::derivation_builtins::builtins(Rc::clone(&io)));
 
     // Add the actual `builtins.derivation` from compiled Nix code
     eval.src_builtins
         .push(("derivation", include_str!("derivation.nix")));
 }
 
+/// Adds fetcher builtins to the passed [tvix_eval::Evaluation]:
+///
+/// * `fetchurl`
+/// * `fetchTarball`
+/// * `fetchGit`
+pub fn add_fetcher_builtins<IO>(eval: &mut tvix_eval::Evaluation<IO>, io: Rc<TvixStoreIO>) {
+    eval.builtins
+        .extend(fetchers::fetcher_builtins::builtins(Rc::clone(&io)));
+}
+
 #[cfg(test)]
 mod tests {
     use std::{rc::Rc, sync::Arc};
 
     use crate::tvix_store_io::TvixStoreIO;
 
-    use super::add_derivation_builtins;
+    use super::{add_derivation_builtins, add_fetcher_builtins};
     use nix_compat::store_path::hash_placeholder;
     use test_case::test_case;
     use tvix_build::buildservice::DummyBuildService;
@@ -57,7 +68,8 @@ mod tests {
 
         let mut eval = tvix_eval::Evaluation::new(io.clone() as Rc<dyn EvalIO>, false);
 
-        add_derivation_builtins(&mut eval, io);
+        add_derivation_builtins(&mut eval, Rc::clone(&io));
+        add_fetcher_builtins(&mut eval, io);
 
         // run the evaluation itself.
         eval.evaluate(str, None)