fix: normalize resolved result on Windows for root (#345)

similar to #322

src/cache.rs

@@ -249,7 +249,7 @@ impl CachedPath {
                 self.0.canonicalizing.store(tid, Ordering::Release);
 
                 let res = self.parent().map_or_else(
-                    || Ok(self.clone()),
+                    || Ok(self.normalize_root(cache)),
                     |parent| {
                         parent.canocalize_impl(cache).and_then(|parent_canonical| {
                             let path = parent_canonical.normalize_with(
@@ -447,6 +447,24 @@ impl CachedPath {
             cache.value(path)
         })
     }
+
+    #[inline]
+    #[cfg(windows)]
+    pub fn normalize_root<Fs: FileSystem>(&self, cache: &Cache<Fs>) -> Self {
+        if self.path().as_os_str().as_encoded_bytes().last() == Some(&b'/') {
+            let mut path_string = self.path.to_string_lossy().into_owned();
+            path_string.pop();
+            path_string.push('\\');
+            cache.value(&PathBuf::from(path_string))
+        } else {
+            self.clone()
+        }
+    }
+    #[inline]
+    #[cfg(not(windows))]
+    pub fn normalize_root<Fs: FileSystem>(&self, _cache: &Cache<Fs>) -> Self {
+        self.clone()
+    }
 }
 
 /// Since the cache key is memoized, use an identity hasher

src/tests/resolve.rs

@@ -121,8 +121,6 @@ fn resolve_hash_as_module() {
 #[cfg(windows)]
 #[test]
 fn resolve_normalized_on_windows() {
-    use std::path::PathBuf;
-
     use normalize_path::NormalizePath;
 
     let f = super::fixture();
@@ -132,9 +130,15 @@ fn resolve_normalized_on_windows() {
     let resolver = Resolver::new(ResolveOptions::default());
 
     let resolution = resolver.resolve(&f, &normalized_absolute).map(|r| r.full_path());
-    assert_eq!(resolution, Ok(PathBuf::from(absolute_str.as_ref())));
+    assert_eq!(
+        resolution.map(|r| r.to_string_lossy().into_owned()),
+        Ok(absolute_str.clone().into_owned())
+    );
 
     let normalized_f = f.to_str().unwrap().replace('\\', "/");
     let resolution = resolver.resolve(normalized_f, ".\\foo\\index.js").map(|r| r.full_path());
-    assert_eq!(resolution, Ok(PathBuf::from(absolute_str.as_ref())));
+    assert_eq!(
+        resolution.map(|r| r.to_string_lossy().into_owned()),
+        Ok(absolute_str.clone().into_owned())
+    );
 }