Improves sourcemap path handling with pathdiff

CHANGELOG.md

@@ -36,12 +36,14 @@ Making a new release? Simply add the new header with the version and date undern
 * Fixed a bug where MacOS paths weren't being handled correctly. ([#1201])
 * Fixed a bug where the notification timeout thread would fail to cancel on unmount ([#1211])
 * Added a "Forget" option to the sync reminder notification to avoid being reminded for that place in the future ([#1215])
+* Improves relative path calculation for sourcemap generation to avoid issues with Windows UNC paths. ([#1217])
 
 [#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
 [#1211]: https://github.com/rojo-rbx/rojo/pull/1211
 [#1215]: https://github.com/rojo-rbx/rojo/pull/1215
+[#1217]: https://github.com/rojo-rbx/rojo/pull/1217
 
 ## [7.7.0-rc.1] (November 27th, 2025)
 

Cargo.toml

@@ -100,6 +100,7 @@ clap = { version = "3.2.25", features = ["derive"] }
 profiling = "1.0.15"
 yaml-rust2 = "0.10.3"
 data-encoding = "2.8.0"
+pathdiff = "0.2.3"
 
 blake3 = "1.5.0"
 float-cmp = "0.9.0"
@@ -122,7 +123,7 @@ semver = "1.0.22"
 rojo-insta-ext = { path = "crates/rojo-insta-ext" }
 
 criterion = "0.3.6"
-insta = { version = "1.36.1", features = ["redactions", "yaml"] }
+insta = { version = "1.36.1", features = ["redactions", "yaml", "json"] }
 paste = "1.0.14"
 pretty_assertions = "1.4.0"
 serde_yaml = "0.8.26"

crates/memofs/src/lib.rs

@@ -657,4 +657,6 @@ mod test {
         let err = vfs.canonicalize(&file_path).unwrap_err();
         assert_eq!(err.kind(), io::ErrorKind::NotFound);
     }
+
+    // TODO: Add a test to check whether new_default uses StdBackend.
 }

src/cli/snapshots/librojo__cli__sourcemap__test__maps_absolute_paths.snap

@@ -0,0 +1,35 @@
+---
+source: src/cli/sourcemap.rs
+expression: sourcemap_contents
+---
+{
+  "name": "default",
+  "className": "DataModel",
+  "filePaths": "[...paths omitted...]",
+  "children": [
+    {
+      "name": "ReplicatedStorage",
+      "className": "ReplicatedStorage",
+      "children": [
+        {
+          "name": "Project",
+          "className": "ModuleScript",
+          "filePaths": "[...paths omitted...]",
+          "children": [
+            {
+              "name": "Module",
+              "className": "Folder",
+              "children": [
+                {
+                  "name": "module",
+                  "className": "ModuleScript",
+                  "filePaths": "[...paths omitted...]"
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}

src/cli/snapshots/librojo__cli__sourcemap__test__maps_relative_paths.snap

@@ -0,0 +1,41 @@
+---
+source: src/cli/sourcemap.rs
+expression: sourcemap_contents
+---
+{
+  "name": "default",
+  "className": "DataModel",
+  "filePaths": [
+    "default.project.json"
+  ],
+  "children": [
+    {
+      "name": "ReplicatedStorage",
+      "className": "ReplicatedStorage",
+      "children": [
+        {
+          "name": "Project",
+          "className": "ModuleScript",
+          "filePaths": [
+            "src/init.luau"
+          ],
+          "children": [
+            {
+              "name": "Module",
+              "className": "Folder",
+              "children": [
+                {
+                  "name": "module",
+                  "className": "ModuleScript",
+                  "filePaths": [
+                    "../module/module.luau"
+                  ]
+                }
+              ]
+            }
+          ]
+        }
+      ]
+    }
+  ]
+}

src/cli/sourcemap.rs

@@ -10,7 +10,7 @@ use fs_err::File;
 use memofs::Vfs;
 use rayon::prelude::*;
 use rbx_dom_weak::{types::Ref, Ustr};
-use serde::Serialize;
+use serde::{Deserialize, Serialize};
 use tokio::runtime::Runtime;
 
 use crate::{
@@ -24,19 +24,20 @@ const PATH_STRIP_FAILED_ERR: &str = "Failed to create relative paths for project
 const ABSOLUTE_PATH_FAILED_ERR: &str = "Failed to turn relative path into absolute path!";
 
 /// Representation of a node in the generated sourcemap tree.
-#[derive(Serialize)]
+#[derive(Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 struct SourcemapNode<'a> {
     name: &'a str,
     class_name: Ustr,
 
     #[serde(
+        default,
         skip_serializing_if = "Vec::is_empty",
         serialize_with = "crate::path_serializer::serialize_vec_absolute"
     )]
     file_paths: Vec<Cow<'a, Path>>,
 
-    #[serde(skip_serializing_if = "Vec::is_empty")]
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
     children: Vec<SourcemapNode<'a>>,
 }
 
@@ -70,12 +71,13 @@ pub struct SourcemapCommand {
 
 impl SourcemapCommand {
     pub fn run(self) -> anyhow::Result<()> {
-        let project_path = resolve_path(&self.project);
+        let project_path = fs_err::canonicalize(resolve_path(&self.project))?;
 
-        log::trace!("Constructing in-memory filesystem");
+        log::trace!("Constructing filesystem with StdBackend");
         let vfs = Vfs::new_default();
         vfs.set_watch_enabled(self.watch);
 
+        log::trace!("Setting up session for sourcemap generation");
         let session = ServeSession::new(vfs, project_path)?;
         let mut cursor = session.message_queue().cursor();
 
@@ -87,14 +89,17 @@ impl SourcemapCommand {
 
         // Pre-build a rayon threadpool with a low number of threads to avoid
         // dynamic creation overhead on systems with a high number of cpus.
+        log::trace!("Setting rayon global threadpool");
         rayon::ThreadPoolBuilder::new()
             .num_threads(num_cpus::get().min(6))
             .build_global()
-            .unwrap();
+            .ok();
 
+        log::trace!("Writing initial sourcemap");
         write_sourcemap(&session, self.output.as_deref(), filter, self.absolute)?;
 
         if self.watch {
+            log::trace!("Setting up runtime for watch mode");
             let rt = Runtime::new().unwrap();
 
             loop {
@@ -141,26 +146,26 @@ fn patch_set_affects_sourcemap(
         !set.removed.is_empty()
             // 2. A newly added instance passes the filter
             || set.added.iter().any(|referent| {
-                let instance = tree
-                    .get_instance(*referent)
-                    .expect("instance did not exist when updating sourcemap");
-                filter(&instance)
-            })
+            let instance = tree
+                .get_instance(*referent)
+                .expect("instance did not exist when updating sourcemap");
+            filter(&instance)
+        })
             // 3. An existing instance has its class name, name,
             // or file paths changed, and passes the filter
             || set.updated.iter().any(|updated| {
-                let changed = updated.changed_class_name.is_some()
-                    || updated.changed_name.is_some()
-                    || updated.changed_metadata.is_some();
-                if changed {
-                    let instance = tree
-                        .get_instance(updated.id)
-                        .expect("instance did not exist when updating sourcemap");
-                    filter(&instance)
-                } else {
-                    false
-                }
-            })
+            let changed = updated.changed_class_name.is_some()
+                || updated.changed_name.is_some()
+                || updated.changed_metadata.is_some();
+            if changed {
+                let instance = tree
+                    .get_instance(updated.id)
+                    .expect("instance did not exist when updating sourcemap");
+                filter(&instance)
+            } else {
+                false
+            }
+        })
     })
 }
 
@@ -208,7 +213,7 @@ fn recurse_create_node<'a>(
     } else {
         for val in file_paths {
             output_file_paths.push(Cow::from(
-                val.strip_prefix(project_dir).expect(PATH_STRIP_FAILED_ERR),
+                pathdiff::diff_paths(val, project_dir).expect(PATH_STRIP_FAILED_ERR),
             ));
         }
     };
@@ -250,3 +255,64 @@ fn write_sourcemap(
 
     Ok(())
 }
+
+#[cfg(test)]
+mod test {
+    use crate::cli::sourcemap::SourcemapNode;
+    use crate::cli::SourcemapCommand;
+    use std::path::Path;
+
+    #[test]
+    fn maps_relative_paths() {
+        let sourcemap_dir = tempfile::tempdir().unwrap();
+        let sourcemap_output = sourcemap_dir.path().join("sourcemap.json");
+        let project_path = fs_err::canonicalize(
+            Path::new(env!("CARGO_MANIFEST_DIR"))
+                .join("test-projects")
+                .join("relative_paths")
+                .join("project"),
+        )
+        .unwrap();
+        let sourcemap_command = SourcemapCommand {
+            project: project_path,
+            output: Some(sourcemap_output.clone()),
+            include_non_scripts: false,
+            watch: false,
+            absolute: false,
+        };
+        assert!(sourcemap_command.run().is_ok());
+
+        let raw_sourcemap_contents = fs_err::read_to_string(sourcemap_output.as_path()).unwrap();
+        let sourcemap_contents =
+            serde_json::from_str::<SourcemapNode>(&raw_sourcemap_contents).unwrap();
+        insta::assert_json_snapshot!(sourcemap_contents);
+    }
+
+    #[test]
+    fn maps_absolute_paths() {
+        let sourcemap_dir = tempfile::tempdir().unwrap();
+        let sourcemap_output = sourcemap_dir.path().join("sourcemap.json");
+        let project_path = fs_err::canonicalize(
+            Path::new(env!("CARGO_MANIFEST_DIR"))
+                .join("test-projects")
+                .join("relative_paths")
+                .join("project"),
+        )
+        .unwrap();
+        let sourcemap_command = SourcemapCommand {
+            project: project_path,
+            output: Some(sourcemap_output.clone()),
+            include_non_scripts: false,
+            watch: false,
+            absolute: true,
+        };
+        assert!(sourcemap_command.run().is_ok());
+
+        let raw_sourcemap_contents = fs_err::read_to_string(sourcemap_output.as_path()).unwrap();
+        let sourcemap_contents =
+            serde_json::from_str::<SourcemapNode>(&raw_sourcemap_contents).unwrap();
+        insta::assert_json_snapshot!(sourcemap_contents, {
+            ".**.filePaths" => "[...paths omitted...]"
+        });
+    }
+}

test-projects/relative_paths/default.project.json

@@ -0,0 +1,14 @@
+{
+  "name": "default",
+  "tree": {
+    "$className": "DataModel",
+    "ReplicatedStorage": {
+      "Project": {
+        "$path": "project/src",
+        "Module": {
+          "$path": "module"
+        }
+      }
+    }
+  }
+}

test-projects/relative_paths/module/module.luau

@@ -0,0 +1 @@
+return nil

test-projects/relative_paths/project/default.project.json

@@ -0,0 +1,14 @@
+{
+  "name": "default",
+  "tree": {
+    "$className": "DataModel",
+    "ReplicatedStorage": {
+      "Project": {
+        "$path": "src/",
+        "Module": {
+          "$path": "../module"
+        }
+      }
+    }
+  }
+}

test-projects/relative_paths/project/src/init.luau

@@ -0,0 +1 @@
+return nil