refactor(tvix/derivation): use BTreeSet for derivation outputs r/5657

When constructing derivations inside builtins.derivationStrict, we'd
have to very frequently check whether certain outputs have already
been inserted into the derivation inputs.

Using a set type is much easier, especially as this has to be ordered
and the source data that is being inserted also comes from a set,
which might let us pass this more efficiently in the future.

Note that the validate function no longer checks the order of the
entries, as that is now guaranteed by the type.

Change-Id: I2fbb984facba3e668075f6f8df8992092368c63d
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7826
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>

1 files changed, 5 insertions, 3 deletions

diff --git a/tvix/derivation/src/tests/mod.rs b/tvix/derivation/src/tests/mod.rs
index cb98a27cdfe4..bd5d9f34cb12 100644
--- a/tvix/derivation/src/tests/mod.rs
+++ b/tvix/derivation/src/tests/mod.rs
@@ -1,5 +1,6 @@
 use crate::derivation::Derivation;
 use crate::output::{Hash, Output};
+use std::collections::BTreeSet;
 use std::fs::File;
 use std::io::Read;
 use std::path::Path;
@@ -272,9 +273,10 @@ fn output_path_construction() {
     );
 
     // assemble foo input_derivations
-    foo_drv
-        .input_derivations
-        .insert(bar_drv_path.to_absolute_path(), vec!["out".to_string()]);
+    foo_drv.input_derivations.insert(
+        bar_drv_path.to_absolute_path(),
+        BTreeSet::from(["out".to_string()]),
+    );
 
     // calculate foo output paths
     let foo_calc_result = foo_drv.calculate_output_paths(