feat: npm workspace and better Deno workspace support (#24334)

Adds much better support for the unstable Deno workspaces as well as
support for npm workspaces. npm workspaces is still lacking in that we
only install packages into the root node_modules folder. We'll make it
smarter over time in order for it to figure out when to add node_modules
folders within packages.

This includes a breaking change in config file resolution where we stop
searching for config files on the first found package.json unless it's
in a workspace. For the previous behaviour, the root deno.json needs to
be updated to be a workspace by adding `"workspace":
["./path-to-pkg-json-folder-goes-here"]`. See details in
https://github.com/denoland/deno_config/pull/66

Closes #24340
Closes #24159
Closes #24161
Closes #22020
Closes #18546
Closes #16106
Closes #24160

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;