Implement VFS Path normalization for improved cross-platform tree synchronization (#1201)

.gitignore

@@ -23,3 +23,6 @@
 # Macos file system junk
 ._*
 .DS_STORE
+
+# JetBrains IDEs
+/.idea/

CHANGELOG.md

@@ -32,9 +32,11 @@ Making a new release? Simply add the new header with the version and date undern
 ## Unreleased
 * Fixed a bug caused by having reference properties (such as `ObjectValue.Value`) that point to an Instance not included in syncback. ([#1179])
 * Fixed instance replacement fallback failing when too many instances needed to be replaced. ([#1192])
+* Fixed a bug where MacOS paths weren't being handled correctly. ([#1201])
 
 [#1179]: https://github.com/rojo-rbx/rojo/pull/1179
 [#1192]: https://github.com/rojo-rbx/rojo/pull/1192
+[#1201]: https://github.com/rojo-rbx/rojo/pull/1201
 
 ## [7.7.0-rc.1] (November 27th, 2025)
 

Cargo.lock

@@ -1319,6 +1319,7 @@ dependencies = [
  "fs-err",
  "notify",
  "serde",
+ "tempfile",
 ]
 
 [[package]]

crates/memofs/CHANGELOG.md

@@ -1,6 +1,7 @@
 # memofs Changelog
 
 ## Unreleased Changes
+* Added `Vfs::canonicalize`. [#1201]
 
 ## 0.3.1 (2025-11-27)
 * Added `Vfs::exists`. [#1169]

crates/memofs/Cargo.toml

@@ -19,3 +19,6 @@ crossbeam-channel = "0.5.12"
 fs-err = "2.11.0"
 notify = "4.0.17"
 serde = { version = "1.0.197", features = ["derive"] }
+
+[dev-dependencies]
+tempfile = "3.10.1"

crates/memofs/src/in_memory_fs.rs

@@ -232,6 +232,33 @@ impl VfsBackend for InMemoryFs {
         }
     }
 
+    // TODO: We rely on Rojo to prepend cwd to any relative path before storing paths
+    // in MemoFS. The current implementation will error if no prepended absolute path
+    // is found. It really only normalizes paths within the provided path's context.
+    // Example: "/Users/username/project/../other/file.txt" ->
+    // "/Users/username/other/file.txt"
+    // Erroneous example: "/Users/../../other/file.txt" -> "/other/file.txt"
+    // This is not very robust. We should implement proper path normalization here or otherwise
+    // warn if we are missing context and can not fully canonicalize the path correctly.
+    fn canonicalize(&mut self, path: &Path) -> io::Result<PathBuf> {
+        let mut normalized = PathBuf::new();
+        for component in path.components() {
+            match component {
+                std::path::Component::ParentDir => {
+                    normalized.pop();
+                }
+                std::path::Component::CurDir => {}
+                _ => normalized.push(component),
+            }
+        }
+
+        let inner = self.inner.lock().unwrap();
+        match inner.entries.get(&normalized) {
+            Some(_) => Ok(normalized),
+            None => not_found(&normalized),
+        }
+    }
+
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
         let inner = self.inner.lock().unwrap();
 

crates/memofs/src/lib.rs

@@ -77,6 +77,7 @@ pub trait VfsBackend: sealed::Sealed + Send + 'static {
     fn metadata(&mut self, path: &Path) -> io::Result<Metadata>;
     fn remove_file(&mut self, path: &Path) -> io::Result<()>;
     fn remove_dir_all(&mut self, path: &Path) -> io::Result<()>;
+    fn canonicalize(&mut self, path: &Path) -> io::Result<PathBuf>;
 
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent>;
     fn watch(&mut self, path: &Path) -> io::Result<()>;
@@ -225,6 +226,11 @@ impl VfsInner {
         self.backend.metadata(path)
     }
 
+    fn canonicalize<P: AsRef<Path>>(&mut self, path: P) -> io::Result<PathBuf> {
+        let path = path.as_ref();
+        self.backend.canonicalize(path)
+    }
+
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
         self.backend.event_receiver()
     }
@@ -413,6 +419,19 @@ impl Vfs {
         self.inner.lock().unwrap().metadata(path)
     }
 
+    /// Normalize a path via the underlying backend.
+    ///
+    /// Roughly equivalent to [`std::fs::canonicalize`][std::fs::canonicalize]. Relative paths are
+    /// resolved against the backend's current working directory (if applicable) and errors are
+    /// surfaced directly from the backend.
+    ///
+    /// [std::fs::canonicalize]: https://doc.rust-lang.org/stable/std/fs/fn.canonicalize.html
+    #[inline]
+    pub fn canonicalize<P: AsRef<Path>>(&self, path: P) -> io::Result<PathBuf> {
+        let path = path.as_ref();
+        self.inner.lock().unwrap().canonicalize(path)
+    }
+
     /// Retrieve a handle to the event receiver for this `Vfs`.
     #[inline]
     pub fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
@@ -540,6 +559,13 @@ impl VfsLock<'_> {
         self.inner.metadata(path)
     }
 
+    /// Normalize a path via the underlying backend.
+    #[inline]
+    pub fn normalize<P: AsRef<Path>>(&mut self, path: P) -> io::Result<PathBuf> {
+        let path = path.as_ref();
+        self.inner.canonicalize(path)
+    }
+
     /// Retrieve a handle to the event receiver for this `Vfs`.
     #[inline]
     pub fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
@@ -555,7 +581,9 @@ impl VfsLock<'_> {
 
 #[cfg(test)]
 mod test {
-    use crate::{InMemoryFs, Vfs, VfsSnapshot};
+    use crate::{InMemoryFs, StdBackend, Vfs, VfsSnapshot};
+    use std::io;
+    use std::path::PathBuf;
 
     /// https://github.com/rojo-rbx/rojo/issues/899
     #[test]
@@ -571,4 +599,62 @@ mod test {
             "bar\nfoo\n\n"
         );
     }
+
+    /// https://github.com/rojo-rbx/rojo/issues/1200
+    #[test]
+    fn canonicalize_in_memory_success() {
+        let mut imfs = InMemoryFs::new();
+        let contents = "Lorem ipsum dolor sit amet.".to_string();
+
+        imfs.load_snapshot("/test/file.txt", VfsSnapshot::file(contents.to_string()))
+            .unwrap();
+
+        let vfs = Vfs::new(imfs);
+
+        assert_eq!(
+            vfs.canonicalize("/test/nested/../file.txt").unwrap(),
+            PathBuf::from("/test/file.txt")
+        );
+        assert_eq!(
+            vfs.read_to_string(vfs.canonicalize("/test/nested/../file.txt").unwrap())
+                .unwrap()
+                .to_string(),
+            contents.to_string()
+        );
+    }
+
+    #[test]
+    fn canonicalize_in_memory_missing_errors() {
+        let imfs = InMemoryFs::new();
+        let vfs = Vfs::new(imfs);
+
+        let err = vfs.canonicalize("test").unwrap_err();
+        assert_eq!(err.kind(), io::ErrorKind::NotFound);
+    }
+
+    #[test]
+    fn canonicalize_std_backend_success() {
+        let contents = "Lorem ipsum dolor sit amet.".to_string();
+        let dir = tempfile::tempdir().unwrap();
+        let file_path = dir.path().join("file.txt");
+        fs_err::write(&file_path, contents.to_string()).unwrap();
+
+        let vfs = Vfs::new(StdBackend::new());
+        let canonicalized = vfs.canonicalize(&file_path).unwrap();
+        assert_eq!(canonicalized, file_path.canonicalize().unwrap());
+        assert_eq!(
+            vfs.read_to_string(&canonicalized).unwrap().to_string(),
+            contents.to_string()
+        );
+    }
+
+    #[test]
+    fn canonicalize_std_backend_missing_errors() {
+        let dir = tempfile::tempdir().unwrap();
+        let file_path = dir.path().join("test");
+
+        let vfs = Vfs::new(StdBackend::new());
+        let err = vfs.canonicalize(&file_path).unwrap_err();
+        assert_eq!(err.kind(), io::ErrorKind::NotFound);
+    }
 }

crates/memofs/src/noop_backend.rs

@@ -1,5 +1,5 @@
 use std::io;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 use crate::{Metadata, ReadDir, VfsBackend, VfsEvent};
 
@@ -50,6 +50,10 @@ impl VfsBackend for NoopBackend {
         Err(io::Error::other("NoopBackend doesn't do anything"))
     }
 
+    fn canonicalize(&mut self, _path: &Path) -> io::Result<PathBuf> {
+        Err(io::Error::other("NoopBackend doesn't do anything"))
+    }
+
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
         crossbeam_channel::never()
     }

crates/memofs/src/std_backend.rs

@@ -106,6 +106,10 @@ impl VfsBackend for StdBackend {
         })
     }
 
+    fn canonicalize(&mut self, path: &Path) -> io::Result<PathBuf> {
+        fs_err::canonicalize(path)
+    }
+
     fn event_receiver(&self) -> crossbeam_channel::Receiver<VfsEvent> {
         self.watcher_receiver.clone()
     }

src/change_processor.rs

@@ -1,12 +1,12 @@
-use std::{
-    fs,
-    sync::{Arc, Mutex},
-};
-
 use crossbeam_channel::{select, Receiver, RecvError, Sender};
 use jod_thread::JoinHandle;
 use memofs::{IoResultExt, Vfs, VfsEvent};
 use rbx_dom_weak::types::{Ref, Variant};
+use std::path::PathBuf;
+use std::{
+    fs,
+    sync::{Arc, Mutex},
+};
 
 use crate::{
     message_queue::MessageQueue,
@@ -114,18 +114,13 @@ struct JobThreadContext {
 }
 
 impl JobThreadContext {
-    fn handle_vfs_event(&self, event: VfsEvent) {
-        log::trace!("Vfs event: {:?}", event);
-
-        // Update the VFS immediately with the event.
-        self.vfs
-            .commit_event(&event)
-            .expect("Error applying VFS change");
-
-        // For a given VFS event, we might have many changes to different parts
-        // of the tree. Calculate and apply all of these changes.
-        let applied_patches = match event {
-            VfsEvent::Create(path) | VfsEvent::Remove(path) | VfsEvent::Write(path) => {
+    /// Computes and applies patches to the DOM for a given file path.
+    ///
+    /// This function finds the nearest ancestor to the given path that has associated instances
+    /// in the tree.
+    /// It then computes and applies changes for each affected instance ID and
+    /// returns a vector of applied patch sets.
+    fn apply_patches(&self, path: PathBuf) -> Vec<AppliedPatchSet> {
         let mut tree = self.tree.lock().unwrap();
         let mut applied_patches = Vec::new();
 
@@ -161,6 +156,29 @@ impl JobThreadContext {
 
         applied_patches
     }
+
+    fn handle_vfs_event(&self, event: VfsEvent) {
+        log::trace!("Vfs event: {:?}", event);
+
+        // Update the VFS immediately with the event.
+        self.vfs
+            .commit_event(&event)
+            .expect("Error applying VFS change");
+
+        // For a given VFS event, we might have many changes to different parts
+        // of the tree. Calculate and apply all of these changes.
+        let applied_patches = match event {
+            VfsEvent::Create(path) | VfsEvent::Write(path) => {
+                self.apply_patches(self.vfs.canonicalize(&path).unwrap())
+            }
+            VfsEvent::Remove(path) => {
+                // MemoFS does not track parent removals yet, so we can canonicalize
+                // the parent path safely and then append the removed path's file name.
+                let parent = path.parent().unwrap();
+                let file_name = path.file_name().unwrap();
+                let parent_normalized = self.vfs.canonicalize(parent).unwrap();
+                self.apply_patches(parent_normalized.join(file_name))
+            }
             _ => {
                 log::warn!("Unhandled VFS event: {:?}", event);
                 Vec::new()

src/snapshot_middleware/csv.rs

@@ -42,7 +42,7 @@ pub fn snapshot_csv(
         .metadata(
             InstanceMetadata::new()
                 .instigating_source(path)
-                .relevant_paths(vec![path.to_path_buf()]),
+                .relevant_paths(vec![vfs.canonicalize(path)?]),
         );
 
     AdjacentMetadata::read_and_apply_all(vfs, path, name, &mut snapshot)?;

src/snapshot_middleware/dir.rs

@@ -62,18 +62,19 @@ pub fn snapshot_dir_no_meta(
         }
     }
 
+    let normalized_path = vfs.canonicalize(path)?;
     let relevant_paths = vec![
-        path.to_path_buf(),
+        normalized_path.clone(),
         // TODO: We shouldn't need to know about Lua existing in this
         // middleware. Should we figure out a way for that function to add
         // relevant paths to this middleware?
-        path.join("init.lua"),
-        path.join("init.luau"),
-        path.join("init.server.lua"),
-        path.join("init.server.luau"),
-        path.join("init.client.lua"),
-        path.join("init.client.luau"),
-        path.join("init.csv"),
+        normalized_path.join("init.lua"),
+        normalized_path.join("init.luau"),
+        normalized_path.join("init.server.lua"),
+        normalized_path.join("init.server.luau"),
+        normalized_path.join("init.client.lua"),
+        normalized_path.join("init.client.luau"),
+        normalized_path.join("init.csv"),
     ];
 
     let snapshot = InstanceSnapshot::new()

src/snapshot_middleware/json.rs

@@ -32,7 +32,7 @@ pub fn snapshot_json(
         .metadata(
             InstanceMetadata::new()
                 .instigating_source(path)
-                .relevant_paths(vec![path.to_path_buf()])
+                .relevant_paths(vec![vfs.canonicalize(path)?])
                 .context(context),
         );
 

src/snapshot_middleware/json_model.rs

@@ -59,7 +59,7 @@ pub fn snapshot_json_model(
     snapshot.metadata = snapshot
         .metadata
         .instigating_source(path)
-        .relevant_paths(vec![path.to_path_buf()])
+        .relevant_paths(vec![vfs.canonicalize(path)?])
         .context(context)
         .specified_id(id)
         .schema(schema);

src/snapshot_middleware/lua.rs

@@ -88,7 +88,7 @@ pub fn snapshot_lua(
         .metadata(
             InstanceMetadata::new()
                 .instigating_source(path)
-                .relevant_paths(vec![path.to_path_buf()])
+                .relevant_paths(vec![vfs.canonicalize(path)?])
                 .context(context),
         );
 

src/snapshot_middleware/rbxm.rs

@@ -28,7 +28,7 @@ pub fn snapshot_rbxm(
             .metadata(
                 InstanceMetadata::new()
                     .instigating_source(path)
-                    .relevant_paths(vec![path.to_path_buf()])
+                    .relevant_paths(vec![vfs.canonicalize(path)?])
                     .context(context),
             );
 

src/snapshot_middleware/rbxmx.rs

@@ -31,7 +31,7 @@ pub fn snapshot_rbxmx(
             .metadata(
                 InstanceMetadata::new()
                     .instigating_source(path)
-                    .relevant_paths(vec![path.to_path_buf()])
+                    .relevant_paths(vec![vfs.canonicalize(path)?])
                     .context(context),
             );
 

src/snapshot_middleware/toml.rs

@@ -31,7 +31,7 @@ pub fn snapshot_toml(
         .metadata(
             InstanceMetadata::new()
                 .instigating_source(path)
-                .relevant_paths(vec![path.to_path_buf()])
+                .relevant_paths(vec![vfs.canonicalize(path)?])
                 .context(context),
         );
 

src/snapshot_middleware/txt.rs

@@ -28,7 +28,7 @@ pub fn snapshot_txt(
         .metadata(
             InstanceMetadata::new()
                 .instigating_source(path)
-                .relevant_paths(vec![path.to_path_buf()])
+                .relevant_paths(vec![vfs.canonicalize(path)?])
                 .context(context),
         );
 

src/snapshot_middleware/yaml.rs

@@ -37,7 +37,7 @@ pub fn snapshot_yaml(
         .metadata(
             InstanceMetadata::new()
                 .instigating_source(path)
-                .relevant_paths(vec![path.to_path_buf()])
+                .relevant_paths(vec![vfs.canonicalize(path)?])
                 .context(context),
         );