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, 6 insertions, 3 deletions

diff --git a/tvix/eval/src/tests/one_offs.rs b/tvix/eval/src/tests/one_offs.rs
index 21e9144baf64..49ed713fc96c 100644
--- a/tvix/eval/src/tests/one_offs.rs
+++ b/tvix/eval/src/tests/one_offs.rs
@@ -5,8 +5,9 @@ fn test_source_builtin() {
     // Test an evaluation with a source-only builtin. The test ensures
     // that the artificially constructed thunking is correct.
 
-    let mut eval = Evaluation::new_pure();
-    eval.src_builtins.push(("testSourceBuiltin", "42"));
+    let eval = Evaluation::builder_pure()
+        .add_src_builtin("testSourceBuiltin", "42")
+        .build();
 
     let result = eval.evaluate("builtins.testSourceBuiltin", None);
     assert!(
@@ -25,7 +26,9 @@ fn test_source_builtin() {
 
 #[test]
 fn skip_broken_bytecode() {
-    let result = Evaluation::new_pure().evaluate(/* code = */ "x", None);
+    let result = Evaluation::builder_pure()
+        .build()
+        .evaluate(/* code = */ "x", None);
 
     assert_eq!(result.errors.len(), 1);