From 8d17ab36c3d901efbdb901d865c09c973de39649 Mon Sep 17 00:00:00 2001
From: Ali Rezvani <3788964+rzvxa@users.noreply.github.com>
Date: Wed, 24 Apr 2024 20:40:59 +0330
Subject: [PATCH] fix(semantic): allow `root_node` to be empty for empty trees.
 (#3084)

related to #3082, #3030 and #3069
---
 crates/oxc_linter/src/rules/oxc/no_barrel_file.rs | 6 +++++-
 crates/oxc_semantic/src/node.rs                   | 5 ++++-
 2 files changed, 9 insertions(+), 2 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 b648756e4..eb7f58689 100644
--- a/crates/oxc_linter/src/rules/oxc/no_barrel_file.rs
+++ b/crates/oxc_linter/src/rules/oxc/no_barrel_file.rs
@@ -52,7 +52,11 @@ impl Rule for NoBarrelFile {
     fn run_once(&self, ctx: &LintContext<'_>) {
         let semantic = ctx.semantic();
         let module_record = semantic.module_record();
-        let Some(root) = ctx.nodes().iter().next() else { return };
+        let root_id = semantic.nodes().root();
+        if root_id == usize::MAX {
+            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 3c9cac77a..582bab68f 100644
--- a/crates/oxc_semantic/src/node.rs
+++ b/crates/oxc_semantic/src/node.rs
@@ -64,7 +64,7 @@ pub struct AstNodes<'a> {
 impl<'a> Default for AstNodes<'a> {
     fn default() -> Self {
         Self {
-            root: AstNodeId::new(0),
+            root: AstNodeId::new(usize::MAX),
             nodes: IndexVec::default(),
             parent_ids: IndexVec::default(),
         }
@@ -110,6 +110,7 @@ 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 {
         self.root
     }
@@ -130,11 +131,13 @@ 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())
     }
 
     /// 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())
     }