From dcb2528861fa2e266ce4345274151327e82df1fa Mon Sep 17 00:00:00 2001
From: Ali Rezvani <3788964+rzvxa@users.noreply.github.com>
Date: Thu, 25 Apr 2024 04:13:49 +0330
Subject: [PATCH] fix(semantic): revert test code pushed to the main by
 accident. (#3085)

I'm terribly sorry, I've reverted the wrong commit in #3084.
---
 .../src/rules/oxc/no_barrel_file.rs           |  8 +++---
 crates/oxc_semantic/src/node.rs               | 27 +++++++------------
 2 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/crates/oxc_linter/src/rules/oxc/no_barrel_file.rs b/crates/oxc_linter/src/rules/oxc/no_barrel_file.rs
index eb7f58689..728b207db 100644
--- a/crates/oxc_linter/src/rules/oxc/no_barrel_file.rs
+++ b/crates/oxc_linter/src/rules/oxc/no_barrel_file.rs
@@ -52,11 +52,11 @@ impl Rule for NoBarrelFile {
     fn run_once(&self, ctx: &LintContext<'_>) {
         let semantic = ctx.semantic();
         let module_record = semantic.module_record();
-        let root_id = semantic.nodes().root();
-        if root_id == usize::MAX {
+        let Some(root) = semantic.nodes().root_node() else {
+            // Return early if the semantic's root node isn't set.
+            // It usually means we are running on an empty or invalid file.
             return;
-        }
-        let root = semantic.nodes().get_node(root_id);
+        };
 
         let AstKind::Program(program) = root.kind() else { unreachable!() };
 
diff --git a/crates/oxc_semantic/src/node.rs b/crates/oxc_semantic/src/node.rs
index 582bab68f..edd53bca9 100644
--- a/crates/oxc_semantic/src/node.rs
+++ b/crates/oxc_semantic/src/node.rs
@@ -54,23 +54,13 @@ impl<'a> AstNode<'a> {
 }
 
 /// Untyped AST nodes flattened into an vec
-#[derive(Debug)]
+#[derive(Debug, Default)]
 pub struct AstNodes<'a> {
-    root: AstNodeId,
+    root: Option<AstNodeId>,
     nodes: IndexVec<AstNodeId, AstNode<'a>>,
     parent_ids: IndexVec<AstNodeId, Option<AstNodeId>>,
 }
 
-impl<'a> Default for AstNodes<'a> {
-    fn default() -> Self {
-        Self {
-            root: AstNodeId::new(usize::MAX),
-            nodes: IndexVec::default(),
-            parent_ids: IndexVec::default(),
-        }
-    }
-}
-
 impl<'a> AstNodes<'a> {
     pub fn iter(&self) -> impl Iterator<Item = &AstNode<'a>> + '_ {
         self.nodes.iter()
@@ -111,7 +101,7 @@ impl<'a> AstNodes<'a> {
 
     /// Get the root `AstNodeId`, It is always pointing to a `Program`.
     /// Returns `None` if root node isn't set.
-    pub fn root(&self) -> AstNodeId {
+    pub fn root(&self) -> Option<AstNodeId> {
         self.root
     }
 
@@ -124,7 +114,7 @@ impl<'a> AstNodes<'a> {
     pub(super) unsafe fn set_root(&mut self, root: &AstNode<'a>) {
         match root.kind() {
             AstKind::Program(_) => {
-                self.root = root.id();
+                self.root = Some(root.id());
             }
             _ => unreachable!("Expected a `Program` node as the root of the tree."),
         }
@@ -132,14 +122,14 @@ impl<'a> AstNodes<'a> {
 
     /// Get the root node as immutable reference, It is always guaranteed to be a `Program`.
     /// Returns `None` if root node isn't set.
-    pub fn root_node(&self) -> &AstNode<'a> {
-        self.get_node(self.root())
+    pub fn root_node(&self) -> Option<&AstNode<'a>> {
+        self.root().map(|id| self.get_node(id))
     }
 
     /// Get the root node as mutable reference, It is always guaranteed to be a `Program`.
     /// Returns `None` if root node isn't set.
-    pub fn root_node_mut(&mut self) -> &mut AstNode<'a> {
-        self.get_node_mut(self.root())
+    pub fn root_node_mut(&mut self) -> Option<&mut AstNode<'a>> {
+        self.root().map(|id| self.get_node_mut(id))
     }
 
     /// Walk up the AST, iterating over each parent node.
@@ -151,6 +141,7 @@ impl<'a> AstNodes<'a> {
         std::iter::successors(Some(ast_node_id), |node_id| parent_ids[*node_id])
     }
 
+    /// Adds an `AstNode` to the `AstNodes` tree and returns its `AstNodeId`.
     pub fn add_node(&mut self, node: AstNode<'a>, parent_id: Option<AstNodeId>) -> AstNodeId {
         let mut node = node;
         let ast_node_id = self.parent_ids.push(parent_id);