perf: bring back the symlink optimization (#298)

fixtures/nested-symlink/apps/tooling

@@ -0,0 +1 @@
+../tooling

fixtures/nested-symlink/apps/web/nm/@repo/typescript-config

@@ -0,0 +1 @@
+../../../../tooling/typescript-config

fixtures/nested-symlink/tooling/typescript-config/index.js

@@ -0,0 +1 @@
+../../nm/index.js

src/file_system.rs

@@ -172,34 +172,47 @@ impl FileSystem for FileSystemOs {
                 }
             } else if #[cfg(windows)] {
                 dunce::canonicalize(path)
-            } else if #[cfg(target_family = "wasm")] {
+            } else {
                 use std::path::Component;
                 let mut path_buf = path.to_path_buf();
                 loop {
                     let link = fs::read_link(&path_buf)?;
                     path_buf.pop();
+                    if fs::symlink_metadata(&path_buf)?.is_symlink()
+                    {
+                      path_buf = self.canonicalize(path_buf.as_path())?;
+                    }
                     for component in link.components() {
                         match component {
                             Component::ParentDir => {
                                 path_buf.pop();
                             }
                             Component::Normal(seg) => {
-                                // Need to trim the extra \0 introduces by https://github.com/nodejs/uvwasi/issues/262
-                                path_buf.push(seg.to_string_lossy().trim_end_matches('\0'));
+                                #[cfg(target_family = "wasm")]
+                                {
+                                  // Need to trim the extra \0 introduces by https://github.com/nodejs/uvwasi/issues/262
+                                  path_buf.push(seg.to_string_lossy().trim_end_matches('\0'));
+                                }
+                                #[cfg(not(target_family = "wasm"))]
+                                {
+                                  path_buf.push(seg);
+                                }
                             }
                             Component::RootDir => {
                                 path_buf = PathBuf::from("/");
                             }
                             Component::CurDir | Component::Prefix(_) => {}
                         }
+                        if fs::symlink_metadata(&path_buf)?.is_symlink()
+                        {
+                          path_buf = self.canonicalize(path_buf.as_path())?;
+                        }
                     }
                     if !fs::symlink_metadata(&path_buf)?.is_symlink() {
                         break;
                     }
                 }
                 Ok(path_buf)
-            } else {
-                fs::canonicalize(path)
             }
         }
     }

tests/resolve_test.rs

@@ -184,3 +184,24 @@ fn decimal_js_from_mathjs() {
         assert_eq!(resolution, Ok(module_path.clone()));
     }
 }
+
+#[test]
+// regression: https://github.com/NicholasLYang/oxc-repro
+fn nested_symlinks() {
+    let dir = dir();
+    let dir = dir.join("fixtures/nested-symlink");
+    assert_eq!(
+        Resolver::new(ResolveOptions::default())
+            // ./apps/web/nm/@repo/typescript-config is a symlink
+            .resolve(&dir, "./apps/web/nm/@repo/typescript-config/index.js")
+            .map(oxc_resolver::Resolution::into_path_buf),
+        Ok(dir.join("nm/index.js"))
+    );
+    assert_eq!(
+        Resolver::new(ResolveOptions::default())
+            // ./apps/tooling is a symlink
+            .resolve(&dir, "./apps/tooling/typescript-config/index.js")
+            .map(oxc_resolver::Resolution::into_path_buf),
+        Ok(dir.join("nm/index.js"))
+    );
+}