feat: error handling

evaluator/nixjit_eval/src/value/attrset.rs

@@ -6,7 +6,7 @@ use std::rc::Rc;
 
 use derive_more::Constructor;
 use hashbrown::hash_map::Entry;
-use hashbrown::{HashMap, HashSet};
+use hashbrown::HashMap;
 use itertools::Itertools;
 
 use nixjit_error::{Error, Result};
@@ -66,12 +66,7 @@ impl AttrSet {
         self.data.insert(sym, val);
     }
 
-    /// Inserts an attribute.
-    ///
-    /// # Panics
-    ///
-    /// This method currently uses `todo!()` and will panic if the attribute
-    /// already exists, indicating that duplicate attribute handling is not yet implemented.
+    /// Inserts an attribute, returns an error if the attribute is already defined.
     pub fn push_attr(&mut self, sym: String, val: Value) -> Result<()> {
         match self.data.entry(sym) {
             Entry::Occupied(occupied) => Err(Error::EvalError(format!(
@@ -114,17 +109,22 @@ impl AttrSet {
     /// Checks if an attribute path exists within the set.
     pub fn has_attr(
         &self,
-        mut path: impl DoubleEndedIterator<Item = Result<String>>,
-    ) -> Result<bool> {
+        mut path: impl DoubleEndedIterator<Item = Result<Value>>,
+    ) -> Result<Value> {
         let mut data = &self.data;
         let last = path.nth_back(0).unwrap();
         for item in path {
-            let Some(Value::AttrSet(attrs)) = data.get(&item?) else {
-                return Ok(false);
+            let Some(Value::AttrSet(attrs)) =
+                data.get(item.unwrap().coerce_to_string()?.as_ref().unwrap_string())
+            else {
+                return Ok(Value::Bool(false));
             };
             data = attrs.as_inner();
         }
-        Ok(data.get(&last?).is_some())
+        Ok(Value::Bool(
+            data.get(last.unwrap().coerce_to_string()?.as_ref().unwrap_string())
+                .is_some(),
+        ))
     }
 
     /// Merges another `AttrSet` into this one, with attributes from `other`
@@ -169,11 +169,11 @@ impl AttrSet {
     }
 
     /// Converts the `AttrSet` to its public-facing representation.
-    pub fn to_public(&self, seen: &mut HashSet<Value>) -> p::Value {
+    pub fn to_public(self) -> p::Value {
         p::Value::AttrSet(p::AttrSet::new(
             self.data
-                .iter()
-                .map(|(sym, value)| (sym.as_str().into(), value.to_public(seen)))
+                .into_iter()
+                .map(|(sym, value)| (sym.into(), value.to_public()))
                 .collect(),
         ))
     }