fix: select

nix-js/runtime-ts/src/helpers.ts

@@ -46,44 +46,50 @@ export const resolvePath = (path: NixValue): string => {
   return Deno.core.ops.op_resolve_path(path_str);
 };
 
-/**
- * Select an attribute from an attribute set
- * Used by codegen for attribute access (e.g., obj.key)
- *
- * @param obj - Attribute set to select from
- * @param key - Key to select
- * @returns The value at obj[key]
- * @throws Error if obj is null/undefined or key not found
- */
-export const select = (obj: NixValue, key: NixValue): NixValue => {
-  const forced_obj = forceAttrs(obj);
-  const forced_key = forceString(key);
+export const select = (obj: NixValue, attrpath: NixValue[]): NixValue => {
+  let attrs = forceAttrs(obj);
 
-  if (!(forced_key in forced_obj)) {
-    throw new Error(`Attribute '${forced_key}' not found`);
+  for (const attr of attrpath.slice(0, -1)) {
+    const key = forceString(attr)
+    if (!(key in attrs)) {
+      throw new Error(`Attribute '${key}' not found`);
+    }
+    const cur = force(attrs[forceString(attr)]);
+    if (!isAttrs(cur)) {
+      // throw new Error(`Attribute '${forced_key}' not found`);
+      // FIXME: error
+      throw new Error(`Attribute not found`);
+    }
+    attrs = cur;
   }
 
-  return forced_obj[forced_key];
+  const last = forceString(attrpath[attrpath.length - 1])
+  if (!(last in attrs)) {
+    throw new Error(`Attribute '${last}' not found`);
+  }
+  return attrs[last];
 };
 
-/**
- * Select an attribute with a default value
- * Used for Nix's `obj.key or default` syntax
- *
- * @param obj - Attribute set to select from
- * @param key - Key to select
- * @param default_val - Value to return if key not found (will be forced if it's a thunk)
- * @returns obj[key] if exists, otherwise force(default_val)
- */
-export const selectWithDefault = (obj: NixValue, key: NixValue, default_val: NixValue): NixValue => {
-  const attrs = forceAttrs(obj);
-  const forced_key = forceString(key);
+export const selectWithDefault = (obj: NixValue, attrpath: NixValue[], default_val: NixValue): NixValue => {
+  let attrs = forceAttrs(obj);
 
-  if (!(forced_key in attrs)) {
-    return force(default_val);
+  for (const attr of attrpath.slice(0, -1)) {
+    const key = forceString(attr)
+    if (!(key in attrs)) {
+      return default_val
+    }
+    const cur = force(attrs[key]);
+    if (!isAttrs(cur)) {
+      return default_val;
+    }
+    attrs = cur;
   }
 
-  return attrs[forced_key];
+  const last = forceString(attrpath[attrpath.length - 1]);
+  if (last in attrs) {
+    return attrs[last]
+  }
+  return default_val;
 };
 
 export const hasAttr = (obj: NixValue, attrpath: NixValue[]): NixBool => {
@@ -93,14 +99,14 @@ export const hasAttr = (obj: NixValue, attrpath: NixValue[]): NixBool => {
   let attrs = obj;
 
   for (const attr of attrpath.slice(0, -1)) {
-    const cur = attrs[forceString(attr)];
+    const cur = force(attrs[forceString(attr)]);
     if (!isAttrs(cur)) {
       return false;
     }
     attrs = cur;
   }
 
-  return true;
+  return forceString(attrpath[attrpath.length - 1]) in attrs;
 };
 
 /**

nix-js/src/codegen.rs

@@ -11,10 +11,15 @@ pub(crate) trait CodegenContext {
     fn get_sym(&self, id: SymId) -> &str;
 }
 
-fn escape_quote_string(s: &str) -> String {
-    let mut escaped = String::with_capacity(s.len() + 2);
+trait EscapeQuote {
+    fn escape_quote(&self) -> String;
+}
+
+impl EscapeQuote for str {
+    fn escape_quote(&self) -> String {
+        let mut escaped = String::with_capacity(self.len() + 2);
         escaped.push('"');
-    for c in s.chars() {
+        for c in self.chars() {
             match c {
                 '\\' => escaped.push_str("\\\\"),
                 '\"' => escaped.push_str("\\\""),
@@ -27,13 +32,14 @@ fn escape_quote_string(s: &str) -> String {
         escaped.push('"');
         escaped
     }
+}
 
 impl<Ctx: CodegenContext> Compile<Ctx> for Ir {
     fn compile(&self, ctx: &Ctx) -> String {
         match self {
             Ir::Int(int) => format!("{int}n"), // Generate BigInt literal
             Ir::Float(float) => float.to_string(),
-            Ir::Str(s) => escape_quote_string(&s.val),
+            Ir::Str(s) => s.val.escape_quote(),
             Ir::Path(p) => {
                 // Path needs runtime resolution for interpolated paths
                 let path_expr = ctx.get_ir(p.expr).compile(ctx);
@@ -62,7 +68,9 @@ impl<Ctx: CodegenContext> Compile<Ctx> for Ir {
                 format!("expr{}", expr_id.0)
             }
             Ir::Builtins(_) => "Nix.builtins".to_string(),
-            &Ir::Builtin(Builtin(name)) => format!("Nix.builtins[\"{}\"]", ctx.get_sym(name)),
+            &Ir::Builtin(Builtin(name)) => {
+                format!("Nix.builtins[{}]", ctx.get_sym(name).escape_quote())
+            }
             Ir::ConcatStrings(x) => x.compile(ctx),
             Ir::HasAttr(x) => x.compile(ctx),
             &Ir::Assert(Assert { assertion, expr }) => {
@@ -145,7 +153,7 @@ impl Func {
         let required = if let Some(req) = &self.param.required {
             let keys: Vec<_> = req
                 .iter()
-                .map(|&sym| format!("\"{}\"", ctx.get_sym(sym)))
+                .map(|&sym| ctx.get_sym(sym).escape_quote())
                 .collect();
             format!("[{}]", keys.join(","))
         } else {
@@ -156,7 +164,7 @@ impl Func {
         let allowed = if let Some(allow) = &self.param.allowed {
             let keys: Vec<_> = allow
                 .iter()
-                .map(|&sym| format!("\"{}\"", ctx.get_sym(sym)))
+                .map(|&sym| ctx.get_sym(sym).escape_quote())
                 .collect();
             format!("[{}]", keys.join(","))
         } else {
@@ -217,47 +225,21 @@ impl<Ctx: CodegenContext> Compile<Ctx> for Let {
 
 impl<Ctx: CodegenContext> Compile<Ctx> for Select {
     fn compile(&self, ctx: &Ctx) -> String {
-        let expr = ctx.get_ir(self.expr).compile(ctx);
-
-        let mut result = expr;
-        let attr_count = self.attrpath.len();
-
-        for (i, attr) in self.attrpath.iter().enumerate() {
-            let is_last = i == attr_count - 1;
-            result = match attr {
-                Attr::Str(sym) => {
-                    let key = ctx.get_sym(*sym);
-                    if let Some(default) = self.default
-                        && is_last
-                    {
-                        let default_val = ctx.get_ir(default).compile(ctx);
-                        format!(
-                            "Nix.selectWithDefault({}, \"{}\", {})",
-                            result, key, default_val
-                        )
+        let lhs = ctx.get_ir(self.expr).compile(ctx);
+        let attrpath = self
+            .attrpath
+            .iter()
+            .map(|attr| match attr {
+                Attr::Str(sym) => ctx.get_sym(*sym).escape_quote(),
+                Attr::Dynamic(expr_id) => ctx.get_ir(*expr_id).compile(ctx),
+            })
+            .join(",");
+        if let Some(default) = self.default {
+            format!("Nix.selectWithDefault({lhs}, [{attrpath}], {})", ctx.get_ir(default).compile(ctx))
         } else {
-                        format!("Nix.select({}, \"{}\")", result, key)
+            format!("Nix.select({lhs}, [{attrpath}])")
         }
     }
-                Attr::Dynamic(expr_id) => {
-                    let key = ctx.get_ir(*expr_id).compile(ctx);
-                    if let Some(default) = self.default
-                        && is_last
-                    {
-                        let default_val = ctx.get_ir(default).compile(ctx);
-                        format!(
-                            "Nix.selectWithDefault({}, {}, {})",
-                            result, key, default_val
-                        )
-                    } else {
-                        format!("Nix.select({}, {})", result, key)
-                    }
-                }
-            };
-        }
-
-        result
-    }
 }
 
 impl<Ctx: CodegenContext> Compile<Ctx> for AttrSet {
@@ -267,7 +249,7 @@ impl<Ctx: CodegenContext> Compile<Ctx> for AttrSet {
         for (&sym, &expr) in &self.stcs {
             let key = ctx.get_sym(sym);
             let value = ctx.get_ir(expr).compile(ctx);
-            attrs.push(format!("{}: {}", escape_quote_string(key), value));
+            attrs.push(format!("{}: {}", key.escape_quote(), value));
         }
 
         for (key_expr, value_expr) in &self.dyns {
@@ -310,9 +292,7 @@ impl<Ctx: CodegenContext> Compile<Ctx> for HasAttr {
             .rhs
             .iter()
             .map(|attr| match attr {
-                Attr::Str(sym) => {
-                    format!("\"{}\"", ctx.get_sym(*sym))
-                }
+                Attr::Str(sym) => ctx.get_sym(*sym).escape_quote(),
                 Attr::Dynamic(expr_id) => ctx.get_ir(*expr_id).compile(ctx),
             })
             .join(",");

nix-js/src/context/downgrade.rs

@@ -105,8 +105,11 @@ impl DowngradeContext for DowngradeCtx<'_> {
                             .rposition(|t| t.current_binding.is_some());
 
                         // Record dependency if both exist
-                        if let (Some(expr_idx), Some(curr_idx)) = (expr_tracker_idx, current_tracker_idx) {
-                            let current_binding = self.dep_tracker_stack[curr_idx].current_binding.unwrap();
+                        if let (Some(expr_idx), Some(curr_idx)) =
+                            (expr_tracker_idx, current_tracker_idx)
+                        {
+                            let current_binding =
+                                self.dep_tracker_stack[curr_idx].current_binding.unwrap();
                             let owner_binding = self.dep_tracker_stack[curr_idx].owner_binding;
 
                             // If referencing from inner scope to outer scope
@@ -120,17 +123,17 @@ impl DowngradeContext for DowngradeCtx<'_> {
                                     tracker.graph.add_edge(from_node, to_node, ());
                                 } else if curr_idx > expr_idx {
                                     // Cross-scope reference: use owner_binding if available
-                                    if let Some(owner) = owner_binding {
-                                        if let (Some(&from_node), Some(&to_node)) = (
+                                    if let Some(owner) = owner_binding
+                                        && let (Some(&from_node), Some(&to_node)) = (
                                             tracker.expr_to_node.get(&owner),
                                             tracker.expr_to_node.get(&expr),
-                                        ) {
+                                        )
+                                    {
                                         tracker.graph.add_edge(from_node, to_node, ());
                                     }
                                 }
                             }
                         }
-                        }
 
                         return Ok(self.new_expr(Ir::ExprRef(expr)));
                     }
@@ -273,7 +276,9 @@ impl DowngradeContext for DowngradeCtx<'_> {
     }
 
     fn get_current_binding(&self) -> Option<ExprId> {
-        self.dep_tracker_stack.last().and_then(|t| t.current_binding)
+        self.dep_tracker_stack
+            .last()
+            .and_then(|t| t.current_binding)
     }
 
     fn set_current_binding(&mut self, expr: Option<ExprId>) {

nix-js/src/error.rs

@@ -121,10 +121,7 @@ impl Error {
         Self::new(ErrorKind::DowngradeError(msg))
     }
     pub fn eval_error(msg: String, backtrace: Option<String>) -> Self {
-        Self::new(ErrorKind::EvalError {
-            msg,
-            backtrace
-        })
+        Self::new(ErrorKind::EvalError { msg, backtrace })
     }
     pub fn internal(msg: String) -> Self {
         Self::new(ErrorKind::InternalError(msg))

nix-js/src/fetcher.rs

@@ -57,21 +57,17 @@ pub fn op_fetch_url(
     let cache = FetcherCache::new().map_err(|e| NixError::from(e.to_string()))?;
     let downloader = Downloader::new();
 
-    let file_name = name.unwrap_or_else(|| {
-        url.rsplit('/')
-            .next()
-            .unwrap_or("download")
-            .to_string()
-    });
+    let file_name =
+        name.unwrap_or_else(|| url.rsplit('/').next().unwrap_or("download").to_string());
 
-    if let Some(ref hash) = expected_hash {
-        if let Some(cached) = cache.get_url(&url, hash) {
+    if let Some(ref hash) = expected_hash
+        && let Some(cached) = cache.get_url(&url, hash)
+    {
         return Ok(FetchUrlResult {
             store_path: cached.to_string_lossy().to_string(),
             hash: hash.clone(),
         });
     }
-    }
 
     let data = downloader
         .download(&url)
@@ -111,11 +107,6 @@ pub fn op_fetch_tarball(
 
     let dir_name = name.unwrap_or_else(|| "source".to_string());
 
-    let is_nar_hash = expected_hash
-        .as_ref()
-        .map(|h| h.starts_with("sha256-"))
-        .unwrap_or(false);
-
     if let Some(ref hash) = expected_hash {
         let normalized = normalize_hash(hash);
         if let Some(cached) = cache.get_tarball(&url, &normalized) {
@@ -134,17 +125,16 @@ pub fn op_fetch_tarball(
     let extracted_path = archive::extract_archive(&data, &temp_dir.path().to_path_buf())
         .map_err(|e| NixError::from(e.to_string()))?;
 
-    let nar_hash = nar::compute_nar_hash(&extracted_path)
-        .map_err(|e| NixError::from(e.to_string()))?;
+    let nar_hash =
+        nar::compute_nar_hash(&extracted_path).map_err(|e| NixError::from(e.to_string()))?;
 
     if let Some(ref expected) = expected_hash {
         let normalized_expected = normalize_hash(expected);
-        let hash_to_compare = if is_nar_hash { &nar_hash } else { &nar_hash };
 
-        if *hash_to_compare != normalized_expected {
+        if nar_hash != normalized_expected {
             return Err(NixError::from(format!(
                 "hash mismatch for '{}': expected {}, got {}",
-                url, normalized_expected, hash_to_compare
+                url, normalized_expected, nar_hash
             )));
         }
     }
@@ -173,7 +163,16 @@ pub fn op_fetch_git(
     let cache = FetcherCache::new().map_err(|e| NixError::from(e.to_string()))?;
     let dir_name = name.unwrap_or_else(|| "source".to_string());
 
-    git::fetch_git(&cache, &url, git_ref.as_deref(), rev.as_deref(), shallow, submodules, all_refs, &dir_name)
+    git::fetch_git(
+        &cache,
+        &url,
+        git_ref.as_deref(),
+        rev.as_deref(),
+        shallow,
+        submodules,
+        all_refs,
+        &dir_name,
+    )
     .map_err(|e| NixError::from(e.to_string()))
 }
 
@@ -187,18 +186,16 @@ pub fn op_fetch_hg(
     let cache = FetcherCache::new().map_err(|e| NixError::from(e.to_string()))?;
     let dir_name = name.unwrap_or_else(|| "source".to_string());
 
-    hg::fetch_hg(&cache, &url, rev.as_deref(), &dir_name)
-        .map_err(|e| NixError::from(e.to_string()))
+    hg::fetch_hg(&cache, &url, rev.as_deref(), &dir_name).map_err(|e| NixError::from(e.to_string()))
 }
 
 fn normalize_hash(hash: &str) -> String {
-    if hash.starts_with("sha256-") {
-        if let Some(b64) = hash.strip_prefix("sha256-") {
-            if let Ok(bytes) = base64_decode(b64) {
+    if hash.starts_with("sha256-")
+        && let Some(b64) = hash.strip_prefix("sha256-")
+        && let Ok(bytes) = base64_decode(b64)
+    {
         return hex::encode(bytes);
     }
-        }
-    }
     hash.to_string()
 }
 
@@ -212,7 +209,9 @@ fn base64_decode(input: &str) -> Result<Vec<u8>, String> {
     let mut bits = 0;
 
     for c in input.bytes() {
-        let value = ALPHABET.iter().position(|&x| x == c)
+        let value = ALPHABET
+            .iter()
+            .position(|&x| x == c)
             .ok_or_else(|| format!("Invalid base64 character: {}", c as char))?;
 
         buffer = (buffer << 6) | (value as u32);

nix-js/src/fetcher/archive.rs

@@ -1,6 +1,6 @@
 use std::fs::{self, File};
 use std::io::Cursor;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 use flate2::read::GzDecoder;
 
@@ -48,7 +48,7 @@ impl ArchiveFormat {
     }
 }
 
-pub fn extract_archive(data: &[u8], dest: &PathBuf) -> Result<PathBuf, ArchiveError> {
+pub fn extract_archive(data: &[u8], dest: &Path) -> Result<PathBuf, ArchiveError> {
     let format = ArchiveFormat::detect("", data);
 
     let temp_dir = dest.join("_extract_temp");
@@ -65,34 +65,34 @@ pub fn extract_archive(data: &[u8], dest: &PathBuf) -> Result<PathBuf, ArchiveEr
     strip_single_toplevel(&temp_dir, dest)
 }
 
-fn extract_tar_gz(data: &[u8], dest: &PathBuf) -> Result<(), ArchiveError> {
+fn extract_tar_gz(data: &[u8], dest: &Path) -> Result<(), ArchiveError> {
     let decoder = GzDecoder::new(Cursor::new(data));
     let mut archive = tar::Archive::new(decoder);
     archive.unpack(dest)?;
     Ok(())
 }
 
-fn extract_tar_xz(data: &[u8], dest: &PathBuf) -> Result<(), ArchiveError> {
+fn extract_tar_xz(data: &[u8], dest: &Path) -> Result<(), ArchiveError> {
     let decoder = xz2::read::XzDecoder::new(Cursor::new(data));
     let mut archive = tar::Archive::new(decoder);
     archive.unpack(dest)?;
     Ok(())
 }
 
-fn extract_tar_bz2(data: &[u8], dest: &PathBuf) -> Result<(), ArchiveError> {
+fn extract_tar_bz2(data: &[u8], dest: &Path) -> Result<(), ArchiveError> {
     let decoder = bzip2::read::BzDecoder::new(Cursor::new(data));
     let mut archive = tar::Archive::new(decoder);
     archive.unpack(dest)?;
     Ok(())
 }
 
-fn extract_tar(data: &[u8], dest: &PathBuf) -> Result<(), ArchiveError> {
+fn extract_tar(data: &[u8], dest: &Path) -> Result<(), ArchiveError> {
     let mut archive = tar::Archive::new(Cursor::new(data));
     archive.unpack(dest)?;
     Ok(())
 }
 
-fn extract_zip(data: &[u8], dest: &PathBuf) -> Result<(), ArchiveError> {
+fn extract_zip(data: &[u8], dest: &Path) -> Result<(), ArchiveError> {
     let cursor = Cursor::new(data);
     let mut archive = zip::ZipArchive::new(cursor)?;
 
@@ -122,7 +122,7 @@ fn extract_zip(data: &[u8], dest: &PathBuf) -> Result<(), ArchiveError> {
     Ok(())
 }
 
-fn strip_single_toplevel(temp_dir: &PathBuf, dest: &PathBuf) -> Result<PathBuf, ArchiveError> {
+fn strip_single_toplevel(temp_dir: &Path, dest: &Path) -> Result<PathBuf, ArchiveError> {
     let entries: Vec<_> = fs::read_dir(temp_dir)?
         .filter_map(|e| e.ok())
         .filter(|e| !e.file_name().to_string_lossy().starts_with('.'))
@@ -131,7 +131,7 @@ fn strip_single_toplevel(temp_dir: &PathBuf, dest: &PathBuf) -> Result<PathBuf,
     let source_dir = if entries.len() == 1 && entries[0].file_type()?.is_dir() {
         entries[0].path()
     } else {
-        temp_dir.clone()
+        temp_dir.to_path_buf()
     };
 
     let final_dest = dest.join("content");
@@ -149,7 +149,7 @@ fn strip_single_toplevel(temp_dir: &PathBuf, dest: &PathBuf) -> Result<PathBuf,
     Ok(final_dest)
 }
 
-fn copy_dir_recursive(src: &PathBuf, dst: &PathBuf) -> Result<(), std::io::Error> {
+fn copy_dir_recursive(src: &Path, dst: &Path) -> Result<(), std::io::Error> {
     fs::create_dir_all(dst)?;
 
     for entry in fs::read_dir(src)? {
@@ -194,7 +194,9 @@ impl std::fmt::Display for ArchiveError {
         match self {
             ArchiveError::IoError(e) => write!(f, "I/O error: {}", e),
             ArchiveError::ZipError(e) => write!(f, "ZIP error: {}", e),
-            ArchiveError::UnsupportedFormat(fmt) => write!(f, "Unsupported archive format: {}", fmt),
+            ArchiveError::UnsupportedFormat(fmt) => {
+                write!(f, "Unsupported archive format: {}", fmt)
+            }
         }
     }
 }

nix-js/src/fetcher/cache.rs

@@ -97,7 +97,8 @@ impl FetcherCache {
             return None;
         }
 
-        let meta: CacheMetadata = serde_json::from_str(&fs::read_to_string(&meta_path).ok()?).ok()?;
+        let meta: CacheMetadata =
+            serde_json::from_str(&fs::read_to_string(&meta_path).ok()?).ok()?;
 
         if meta.hash == expected_hash {
             Some(data_path)
@@ -166,7 +167,8 @@ impl FetcherCache {
             return None;
         }
 
-        let meta: CacheMetadata = serde_json::from_str(&fs::read_to_string(&meta_path).ok()?).ok()?;
+        let meta: CacheMetadata =
+            serde_json::from_str(&fs::read_to_string(&meta_path).ok()?).ok()?;
 
         if meta.hash == expected_hash {
             Some(self.make_store_path(&meta.hash, &meta.name))

nix-js/src/fetcher/git.rs

@@ -2,8 +2,8 @@ use std::fs;
 use std::path::PathBuf;
 use std::process::Command;
 
-use super::cache::FetcherCache;
 use super::FetchGitResult;
+use super::cache::FetcherCache;
 
 pub fn fetch_git(
     cache: &FetcherCache,
@@ -72,10 +72,7 @@ fn fetch_repo(repo: &PathBuf, all_refs: bool) -> Result<(), GitError> {
         args.push("--all");
     }
 
-    let output = Command::new("git")
-        .args(args)
-        .current_dir(repo)
-        .output()?;
+    let output = Command::new("git").args(args).current_dir(repo).output()?;
 
     if !output.status.success() {
         return Err(GitError::CommandFailed {
@@ -87,7 +84,11 @@ fn fetch_repo(repo: &PathBuf, all_refs: bool) -> Result<(), GitError> {
     Ok(())
 }
 
-fn resolve_rev(repo: &PathBuf, git_ref: Option<&str>, rev: Option<&str>) -> Result<String, GitError> {
+fn resolve_rev(
+    repo: &PathBuf,
+    git_ref: Option<&str>,
+    rev: Option<&str>,
+) -> Result<String, GitError> {
     if let Some(rev) = rev {
         return Ok(rev.to_string());
     }
@@ -263,7 +264,7 @@ fn days_to_ymd(days: u64) -> (u64, u64, u64) {
 }
 
 fn is_leap_year(y: u64) -> bool {
-    (y % 4 == 0 && y % 100 != 0) || (y % 400 == 0)
+    (y.is_multiple_of(4) && !y.is_multiple_of(100)) || y.is_multiple_of(400)
 }
 
 trait Pipe: Sized {

nix-js/src/fetcher/hg.rs

@@ -2,8 +2,8 @@ use std::fs;
 use std::path::PathBuf;
 use std::process::Command;
 
-use super::cache::FetcherCache;
 use super::FetchHgResult;
+use super::cache::FetcherCache;
 
 pub fn fetch_hg(
     cache: &FetcherCache,