strip UNC prefix on windows paths

crates/next-dev/Cargo.toml

@@ -42,6 +42,7 @@ rustls-tls = ["next-core/rustls-tls"]
 anyhow = { version = "1.0.47", features = ["backtrace"] }
 clap = { version = "4.0.18", features = ["derive", "env"], optional = true }
 console-subscriber = { version = "0.1.8", optional = true }
+dunce = "1.0.3"
 futures = "0.3.25"
 mime = "0.3.16"
 next-core = { path = "../next-core" }

crates/next-dev/src/lib.rs

@@ -17,6 +17,7 @@ use std::{
 
 use anyhow::{anyhow, Context, Result};
 use devserver_options::DevServerOptions;
+use dunce::canonicalize;
 use next_core::{
     create_app_source, create_page_source, create_web_entry_source, env::load_env,
     manifest::DevManifestContentSource, next_config::load_next_config,
@@ -421,15 +422,15 @@ pub async fn start_server(options: &DevServerOptions) -> Result<()> {
     let dir = options
         .dir
         .as_ref()
-        .map(|dir| dir.canonicalize())
+        .map(|dir| canonicalize(dir))
         .unwrap_or_else(current_dir)
         .context("project directory can't be found")?
         .to_str()
         .context("project directory contains invalid characters")?
         .to_string();
 
     let root_dir = if let Some(root) = options.root.as_ref() {
-        root.canonicalize()
+        canonicalize(root)
             .context("root directory can't be found")?
             .to_str()
             .context("root directory contains invalid characters")?

crates/turbo-tasks-fs/Cargo.toml

@@ -18,6 +18,7 @@ auto-hash-map = { path = "../auto-hash-map" }
 bitflags = "1.3.2"
 bytes = "1.1.0"
 concurrent-queue = "1.2.2"
+dunce = "1.0.3"
 futures = "0.3.25"
 futures-retry = "0.6.0"
 include_dir = { version = "0.7.2", features = ["nightly"] }

crates/turbo-tasks-fs/src/embed/file.rs

@@ -1,15 +1,16 @@
 use std::path::PathBuf;
 
 use anyhow::{Context, Result};
+use dunce::canonicalize;
 
 use crate::{DiskFileSystemVc, File, FileContentVc, FileSystem};
 
 #[turbo_tasks::function]
 pub async fn content_from_relative_path(package_path: &str, path: &str) -> Result<FileContentVc> {
     let package_path = PathBuf::from(package_path);
     let resolved_path = package_path.join(path);
-    let resolved_path = std::fs::canonicalize(&resolved_path)
-        .context("failed to canonicalize embedded file path")?;
+    let resolved_path =
+        canonicalize(&resolved_path).context("failed to canonicalize embedded file path")?;
     let root_path = resolved_path.parent().unwrap();
     let path = resolved_path.file_name().unwrap().to_str().unwrap();
 

crates/turbo-tasks-fs/src/lib.rs

@@ -270,7 +270,8 @@ impl DiskFileSystem {
     }
 
     pub async fn to_sys_path(&self, fs_path: FileSystemPathVc) -> Result<PathBuf> {
-        let path = Path::new(&self.root);
+        // just in case there's a windows unc path prefix we remove it with `dunce`
+        let path = dunce::simplified(Path::new(&self.root));
         let fs_path = fs_path.await?;
         Ok(if fs_path.path.is_empty() {
             path.to_path_buf()