refactor(tvix/eval): Builderize Evaluation r/8351

Make constructing of a new Evaluation use the builder pattern rather
than setting public mutable fields. This is currently a pure
refactor (no functionality has changed) but has a few advantages:

- We've encapsulated the internals of the fields in Evaluation, meaning
  we can change them without too much breakage of clients
- We have type safety that prevents us from ever changing the fields of
  an Evaluation after it's built (which matters more in a world where we
  reuse Evaluations).

More importantly, this paves the road for doing different things with
the construction of an Evaluation - notably, sharing certain things like
the GlobalsMap across subsequent evaluations in eg the REPL.

Fixes: b/262
Change-Id: I4a27116faac14cdd144fc7c992d14ae095a1aca4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11956
Tested-by: BuildkiteCI
Autosubmit: aspen <root@gws.fyi>
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 12 insertions, 10 deletions

diff --git a/tvix/glue/src/tests/mod.rs b/tvix/glue/src/tests/mod.rs
index 5b474be73657..142ae1a07714 100644
--- a/tvix/glue/src/tests/mod.rs
+++ b/tvix/glue/src/tests/mod.rs
@@ -47,16 +47,18 @@ fn eval_test(code_path: PathBuf, expect_success: bool) {
         tokio_runtime.handle().clone(),
     ));
     // Wrap with TvixIO, so <nix/fetchurl.nix can be imported.
-    let mut eval = tvix_eval::Evaluation::new(
-        Box::new(TvixIO::new(tvix_store_io.clone() as Rc<dyn EvalIO>)) as Box<dyn EvalIO>,
-        true,
-    );
-
-    eval.strict = true;
-    add_derivation_builtins(&mut eval, tvix_store_io.clone());
-    add_fetcher_builtins(&mut eval, tvix_store_io.clone());
-    add_import_builtins(&mut eval, tvix_store_io.clone());
-    configure_nix_path(&mut eval, &None);
+    let mut eval_builder = tvix_eval::Evaluation::builder(Box::new(TvixIO::new(
+        tvix_store_io.clone() as Rc<dyn EvalIO>,
+    )) as Box<dyn EvalIO>)
+    .enable_import()
+    .strict();
+
+    eval_builder = add_derivation_builtins(eval_builder, Rc::clone(&tvix_store_io));
+    eval_builder = add_fetcher_builtins(eval_builder, Rc::clone(&tvix_store_io));
+    eval_builder = add_import_builtins(eval_builder, tvix_store_io);
+    eval_builder = configure_nix_path(eval_builder, &None);
+
+    let eval = eval_builder.build();
 
     let result = eval.evaluate(code, Some(code_path.clone()));
     let failed = match result.value {