ForceMode

fix-vm/src/lib.rs

@@ -13,7 +13,7 @@ use fix_common::StringId;
 use fix_error::{Error, Result, Source};
 use gc_arena::arena::CollectionPhase;
 use gc_arena::{Arena, Collect, Gc, Mutation, RefLock, Rootable};
-use hashbrown::HashMap;
+use hashbrown::{HashMap, HashSet};
 use num_enum::TryFromPrimitive;
 use smallvec::SmallVec;
 
@@ -115,6 +115,16 @@ impl<T: VmRuntimeCtx> VmRuntimeCtxExt for T {
     }
 
     fn convert_value(&self, val: Value) -> fix_common::Value {
+        self.convert_value_with_seen(val, &mut HashSet::new())
+    }
+}
+
+trait ConvertValueWithSeen: VmRuntimeCtx {
+    fn convert_value_with_seen(&self, val: Value, seen: &mut HashSet<u64>) -> fix_common::Value;
+}
+
+impl<T: VmRuntimeCtx> ConvertValueWithSeen for T {
+    fn convert_value_with_seen(&self, val: Value, seen: &mut HashSet<u64>) -> fix_common::Value {
         use fix_common::Value;
         if let Some(i) = val.as_inline::<i32>() {
             Value::Int(i as i64)
@@ -132,26 +142,44 @@ impl<T: VmRuntimeCtx> VmRuntimeCtxExt for T {
         } else if let Some(ns) = val.as_gc::<NixString>() {
             Value::String(ns.as_str().to_owned())
         } else if let Some(attrs) = val.as_gc::<AttrSet>() {
+            let bits = val.to_bits();
+            if attrs.is_empty() {
+                return Value::AttrSet(Default::default());
+            }
+            if !seen.insert(bits) {
+                return Value::Repeated;
+            }
             let mut map = std::collections::BTreeMap::new();
             for &(key, val) in attrs.iter() {
                 let key = self.resolve_string(key).to_owned();
-                let converted = self.convert_value(val);
+                let converted = self.convert_value_with_seen(val, seen);
                 map.insert(fix_common::Symbol::from(key), converted);
             }
             Value::AttrSet(fix_common::AttrSet::new(map))
         } else if let Some(list) = val.as_gc::<List>() {
+            let bits = val.to_bits();
+            if list.inner.borrow().is_empty() {
+                return Value::List(Default::default());
+            }
+            if !seen.insert(bits) {
+                return Value::Repeated;
+            }
             let items: Vec<_> = list
                 .inner
                 .borrow()
                 .iter()
                 .copied()
-                .map(|v| self.convert_value(v))
+                .map(|v| self.convert_value_with_seen(v, seen))
                 .collect();
             Value::List(fix_common::List::new(items))
         } else if val.is::<Closure>() {
             Value::Func
-        } else if val.is::<Thunk>() {
-            Value::Thunk
+        } else if let Some(thunk) = val.as_gc::<Thunk>() {
+            if let ThunkState::Evaluated(v) = *thunk.borrow() {
+                self.convert_value_with_seen(v.relax(), seen)
+            } else {
+                Value::Thunk
+            }
         } else if let Some(primop) = val.as_inline::<PrimOp>() {
             let name = fix_builtins::BUILTINS[primop.id as usize].0;
             Value::PrimOp(name.strip_prefix("__").unwrap_or(name))
@@ -278,7 +306,10 @@ fn init_builtins<'gc>(mc: &Mutation<'gc>, ctx: &mut impl VmRuntimeCtx) -> Value<
     entries.sort_by_key(|(k, _)| *k);
 
     let builtins_set = Gc::new(mc, AttrSet::from_sorted_unchecked(entries));
-    Value::new_gc(builtins_set)
+    let builtins_value = Value::new_gc(builtins_set);
+    *self_ref_thunk.borrow_mut(mc) =
+        ThunkState::Evaluated(builtins_value.restrict().expect("builtins is not a thunk"));
+    builtins_value
 }
 
 impl<'gc> Vm<'gc> {