3 files changed, 42 insertions, 0 deletions
diff --git a/cli/util/collections.rs b/cli/util/collections.rs
new file mode 100644
index 000000000..21f73024b
--- /dev/null
+++ b/cli/util/collections.rs
@@ -0,0 +1,38 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+use std::marker::PhantomData;
+
+pub struct CheckedSet<T: std::hash::Hash + ?Sized> {
+  _kind: PhantomData<T>,
+  checked: std::collections::HashSet<u64>,
+}
+
+impl<T: std::hash::Hash + ?Sized> Default for CheckedSet<T> {
+  fn default() -> Self {
+    Self {
+      _kind: Default::default(),
+      checked: Default::default(),
+    }
+  }
+}
+
+impl<T: std::hash::Hash + ?Sized> CheckedSet<T> {
+  pub fn with_capacity(capacity: usize) -> Self {
+    Self {
+      _kind: PhantomData,
+      checked: std::collections::HashSet::with_capacity(capacity),
+    }
+  }
+
+  pub fn insert(&mut self, value: &T) -> bool {
+    self.checked.insert(self.get_hash(value))
+  }
+
+  fn get_hash(&self, value: &T) -> u64 {
+    use std::collections::hash_map::DefaultHasher;
+    use std::hash::Hasher;
+    let mut hasher = DefaultHasher::new();
+    value.hash(&mut hasher);
+    hasher.finish()
+  }
+}
diff --git a/cli/util/file_watcher.rs b/cli/util/file_watcher.rs
index b2628760b..176ca43f0 100644
--- a/cli/util/file_watcher.rs
+++ b/cli/util/file_watcher.rs
@@ -163,6 +163,9 @@ pub struct WatcherCommunicator {
 
 impl WatcherCommunicator {
   pub fn watch_paths(&self, paths: Vec<PathBuf>) -> Result<(), AnyError> {
+    if paths.is_empty() {
+      return Ok(());
+    }
     self.paths_to_watch_tx.send(paths).map_err(AnyError::from)
   }
 
diff --git a/cli/util/mod.rs b/cli/util/mod.rs
index 89df7bb98..69cdc77c3 100644
--- a/cli/util/mod.rs
+++ b/cli/util/mod.rs
@@ -2,6 +2,7 @@
 
 // Note: Only add code in this folder that has no application specific logic
 pub mod checksum;
+pub mod collections;
 pub mod console;
 pub mod diff;
 pub mod display;