feat(tvix/eval): unthunk empty lists and attribute sets r/6205

Change-Id: Ie66cb1b163a544d45d113fd0f866286f230b0188
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7960
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>

2 files changed, 8 insertions, 0 deletions

diff --git a/tvix/eval/src/compiler/bindings.rs b/tvix/eval/src/compiler/bindings.rs
index 2e703aadc8..a3d7c6fbfb 100644
--- a/tvix/eval/src/compiler/bindings.rs
+++ b/tvix/eval/src/compiler/bindings.rs
@@ -658,6 +658,10 @@ impl Compiler<'_> {
         if kind.is_attrs() {
             self.push_op(OpCode::OpAttrs(Count(count)), node);
         }
+
+        if count == 0 {
+            self.unthunk();
+        }
     }
 
     /// Compile a standard `let ...; in ...` expression.
diff --git a/tvix/eval/src/compiler/mod.rs b/tvix/eval/src/compiler/mod.rs
index bfb823b673..c7061c77a0 100644
--- a/tvix/eval/src/compiler/mod.rs
+++ b/tvix/eval/src/compiler/mod.rs
@@ -592,6 +592,10 @@ impl Compiler<'_> {
             self.scope_mut().mark_initialised(item_slot);
         }
 
+        if count == 0 {
+            self.unthunk();
+        }
+
         self.push_op(OpCode::OpList(Count(count)), node);
         self.scope_mut().end_scope();
     }