Fix: On Windows, Unix slashes of watched paths normalize to Windows slashes.

notify/src/windows.rs

@@ -14,7 +14,7 @@ use std::env;
 use std::ffi::OsString;
 use std::os::raw::c_void;
 use std::os::windows::ffi::{OsStrExt, OsStringExt};
-use std::path::{Path, PathBuf};
+use std::path::{Component, Path, PathBuf, Prefix};
 use std::ptr;
 use std::slice;
 use std::sync::{Arc, Mutex};
@@ -528,18 +528,38 @@ impl ReadDirectoryChangesWatcher {
     }
 
     fn watch_inner(&mut self, path: &Path, recursive_mode: RecursiveMode) -> Result<()> {
-        let pb = if path.is_absolute() {
-            path.to_owned()
-        } else {
-            let p = env::current_dir().map_err(Error::io)?;
-            p.join(path)
+        let pb = path
+            .canonicalize()
+            .map_err(|e| Error::io(e).add_path(path.to_path_buf()))?;
+        let pb = {
+            let mut comps = pb.components();
+            match comps.next() {
+                Some(Component::Prefix(p)) => match p.kind() {
+                    Prefix::VerbatimDisk(drive) => {
+                        // \\?\C:\ -> C:\
+                        let mut out = PathBuf::from(format!("{}:", drive as char));
+                        for c in comps {
+                            out.push(c.as_os_str());
+                        }
+                        out
+                    }
+                    Prefix::VerbatimUNC(server, share) => {
+                        // \\?\UNC\server\share\ -> \\server\share\
+                        let mut root = OsString::from(r"\\");
+                        root.push(server);
+                        root.push("\\");
+                        root.push(share);
+                        let mut out = PathBuf::from(root);
+                        for c in comps {
+                            out.push(c.as_os_str());
+                        }
+                        out
+                    }
+                    _ => pb,
+                },
+                _ => pb,
+            }
         };
-        // path must exist and be either a file or directory
-        if !pb.is_dir() && !pb.is_file() {
-            return Err(Error::generic(
-                "Input watch path is neither a file nor a directory.",
-            ));
-        }
         self.send_action_require_ack(Action::Watch(pb.clone(), recursive_mode), &pb)
     }
 
@@ -600,3 +620,49 @@ impl Drop for ReadDirectoryChangesWatcher {
 unsafe impl Send for ReadDirectoryChangesWatcher {}
 // Because all public methods are `&mut self` it's also perfectly safe to share references.
 unsafe impl Sync for ReadDirectoryChangesWatcher {}
+
+/// https://github.com/notify-rs/notify/issues/687
+#[test]
+fn test_mixed_slashes_are_normalized() {
+    use crate::{ReadDirectoryChangesWatcher, RecursiveMode, Watcher};
+    use std::fs::{self, File};
+    use std::path::Path;
+    use std::sync::mpsc;
+    use std::time::Duration;
+    use tempfile::TempDir;
+
+    let temp_dir = TempDir::new().unwrap();
+    let subfolder_path = temp_dir.path().join("subfolder");
+    fs::create_dir_all(&subfolder_path).unwrap();
+
+    let file_path = subfolder_path.join("dep.txt");
+
+    File::create(&file_path).unwrap();
+
+    let (tx, rx) = mpsc::channel();
+    let mut watcher = ReadDirectoryChangesWatcher::new(tx, Default::default()).unwrap();
+
+    // Replace backslashes with forward slashes in the temp_dir path.
+    let temp_dir_path = temp_dir.path().to_string_lossy().replace('\\', "/");
+    watcher
+        .watch(Path::new(&temp_dir_path), RecursiveMode::Recursive)
+        .unwrap();
+
+    // Remove the file to trigger the event
+    fs::remove_file(&file_path).unwrap();
+
+    // Check the events received
+    let event = rx
+        .recv_timeout(Duration::from_secs(1))
+        .expect("timeout")
+        .expect("unexpected error event");
+
+    assert!(
+        event.paths.iter().any(|p| {
+            let path_str = p.to_string_lossy();
+            path_str.contains('\\') && !path_str.contains('/') && !path_str.starts_with("\\\\?\\")
+        }),
+        "Path \"{}\" should only contain Windows slashes and not start with \"\\\\?\\\"",
+        event.paths.last().unwrap().display()
+    );
+}