feat(resolver): check for directory before loading a directory (#590)

crates/oxc_resolver/src/cache.rs

@@ -26,9 +26,16 @@ impl<Fs: FileSystem> Cache<Fs> {
     }
 
     pub fn is_file(&self, path: &Path) -> bool {
-        self.cache_value(path).meta(&self.fs).is_some_and(|m| m.is_file)
+        self.cache_value(path).is_file(&self.fs)
     }
 
+    pub fn is_dir(&self, path: &Path) -> bool {
+        self.cache_value(path).is_dir(&self.fs)
+    }
+
+    /// # Panics
+    ///
+    /// * Path is file but does not have a parent
     pub fn dirname(&self, path: &Path) -> PathBuf {
         (if self.is_file(path) { path.parent().unwrap() } else { path }).to_path_buf()
     }
@@ -97,6 +104,14 @@ impl CacheValue {
         *self.meta.get_or_init(|| fs.metadata(&self.path).ok())
     }
 
+    fn is_file<Fs: FileSystem>(&self, fs: &Fs) -> bool {
+        self.meta(fs).is_some_and(|meta| meta.is_file)
+    }
+
+    fn is_dir<Fs: FileSystem>(&self, fs: &Fs) -> bool {
+        self.meta(fs).is_some_and(|meta| meta.is_dir)
+    }
+
     fn symlink<Fs: FileSystem>(&self, fs: &Fs) -> Option<PathBuf> {
         self.symlink.get_or_init(|| fs.canonicalize(&self.path).ok()).clone()
     }

crates/oxc_resolver/src/file_system.rs

@@ -37,11 +37,18 @@ pub trait FileSystem: Default + Send + Sync {
 #[derive(Debug, Clone, Copy)]
 pub struct FileMetadata {
     pub(crate) is_file: bool,
+    pub(crate) is_dir: bool,
 }
 
 impl FileMetadata {
-    pub fn new(is_file: bool) -> Self {
-        Self { is_file }
+    pub fn new(is_file: bool, is_dir: bool) -> Self {
+        Self { is_file, is_dir }
+    }
+}
+
+impl From<fs::Metadata> for FileMetadata {
+    fn from(metadata: fs::Metadata) -> Self {
+        Self::new(metadata.is_file(), metadata.is_dir())
     }
 }
 
@@ -55,7 +62,7 @@ impl FileSystem for FileSystemOs {
     }
 
     fn metadata<P: AsRef<Path>>(&self, path: P) -> io::Result<FileMetadata> {
-        fs::metadata(path).map(|metadata| FileMetadata { is_file: metadata.is_file() })
+        fs::metadata(path).map(FileMetadata::from)
     }
 
     fn canonicalize<P: AsRef<Path>>(&self, path: P) -> io::Result<PathBuf> {

crates/oxc_resolver/src/lib.rs

@@ -268,8 +268,10 @@ impl<Fs: FileSystem> ResolverGeneric<Fs> {
                 }
             }
             // c. LOAD_AS_DIRECTORY(DIR/X)
-            if let Some(path) = self.load_as_directory(&node_module_file)? {
-                return Ok(Some(path));
+            if self.cache.is_dir(&node_module_file) {
+                if let Some(path) = self.load_as_directory(&node_module_file)? {
+                    return Ok(Some(path));
+                }
             }
         }
         Ok(None)

crates/oxc_resolver/tests/memory_fs.rs

@@ -58,7 +58,8 @@ impl FileSystem for MemoryFS {
             .metadata(path.as_ref().to_string_lossy().as_ref())
             .map_err(|err| io::Error::new(io::ErrorKind::NotFound, err))?;
         let is_file = metadata.file_type == vfs::VfsFileType::File;
-        Ok(FileMetadata::new(is_file))
+        let is_dir = metadata.file_type == vfs::VfsFileType::Directory;
+        Ok(FileMetadata::new(is_file, is_dir))
     }
 
     fn canonicalize<P: AsRef<Path>>(&self, path: P) -> io::Result<PathBuf> {