fix(tvix/eval): handle thunks in arithmetic builtins r/4960

The simplest solution seems to be to pass references to arithmetic_op!()
which avoids the moving annoyance we had to deal with in the
builtins (no more popping!). We then use .force() to force the values
and dereference any Thunks (which arithmetic_op! doesn't do for us).

Change-Id: I0eb8ad60e80a0b3ba9d9f411e973ef8bcf136989
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6724
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Reviewed-by: tazjin <tazjin@tvl.su>

1 files changed, 20 insertions, 20 deletions

diff --git a/tvix/eval/src/builtins/mod.rs b/tvix/eval/src/builtins/mod.rs
index 650cfe674f..1a6155a823 100644
--- a/tvix/eval/src/builtins/mod.rs
+++ b/tvix/eval/src/builtins/mod.rs
@@ -52,11 +52,11 @@ pub fn coerce_value_to_path(v: &Value, vm: &mut VM) -> Result<PathBuf, ErrorKind
 /// WASM).
 fn pure_builtins() -> Vec<Builtin> {
     vec![
-        Builtin::new("add", &[true, true], |mut args, _| {
-            let b = args.pop().unwrap();
-            let a = args.pop().unwrap();
-            arithmetic_op!(a, b, +)
-        }),
+        Builtin::new(
+            "add",
+            &[false, false],
+            |args, vm| arithmetic_op!(&*args[0].force(vm)?, &*args[1].force(vm)?, +),
+        ),
         Builtin::new("abort", &[true], |args, _| {
             return Err(ErrorKind::Abort(args[0].to_str()?.to_string()));
         }),
@@ -115,11 +115,11 @@ fn pure_builtins() -> Vec<Builtin> {
                 std::cmp::Ordering::Greater => Ok(Value::Integer(1)),
             }
         }),
-        Builtin::new("div", &[true, true], |mut args, _| {
-            let b = args.pop().unwrap();
-            let a = args.pop().unwrap();
-            arithmetic_op!(a, b, /)
-        }),
+        Builtin::new(
+            "div",
+            &[false, false],
+            |args, vm| arithmetic_op!(&*args[0].force(vm)?, &*args[1].force(vm)?, /),
+        ),
         Builtin::new("elemAt", &[true, true], |args, _| {
             let xs = args[0].to_list()?;
             let i = args[1].as_int()?;
@@ -215,11 +215,11 @@ fn pure_builtins() -> Vec<Builtin> {
             let value = args[0].force(vm)?;
             Ok(Value::Bool(matches!(*value, Value::String(_))))
         }),
-        Builtin::new("mul", &[true, true], |mut args, _| {
-            let b = args.pop().unwrap();
-            let a = args.pop().unwrap();
-            arithmetic_op!(a, b, *)
-        }),
+        Builtin::new(
+            "mul",
+            &[false, false],
+            |args, vm| arithmetic_op!(&*args[0].force(vm)?, &*args[1].force(vm)?, *),
+        ),
         Builtin::new("splitVersion", &[true], |args, _| {
             let s = args[0].to_str()?;
             let s = VersionPartsIter::new(s.as_str());
@@ -234,11 +234,11 @@ fn pure_builtins() -> Vec<Builtin> {
                 .collect::<Vec<Value>>();
             Ok(Value::List(NixList::construct(parts.len(), parts)))
         }),
-        Builtin::new("sub", &[true, true], |mut args, _| {
-            let b = args.pop().unwrap();
-            let a = args.pop().unwrap();
-            arithmetic_op!(a, b, -)
-        }),
+        Builtin::new(
+            "sub",
+            &[false, false],
+            |args, vm| arithmetic_op!(&*args[0].force(vm)?, &*args[1].force(vm)?, -),
+        ),
         Builtin::new("substring", &[true, true, true], |args, _| {
             let beg = args[0].as_int()?;
             let len = args[1].as_int()?;