From 95b29d50038957473c40287f7de4f501e7ecc52d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hu=C3=A1ng=20J=C3=B9nli=C3=A0ng?= <jlhwung@gmail.com>
Date: Mon, 26 Feb 2024 16:01:11 -0500
Subject: [PATCH 1/2] fix: avoid popContext on unvisited node paths

---
 .../fixtures/do-expressions/regression-16293/input.js |  5 +++++
 .../do-expressions/regression-16293/output.js         |  5 +++++
 packages/babel-traverse/src/context.ts                | 11 +++++++----
 3 files changed, 17 insertions(+), 4 deletions(-)
 create mode 100644 packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/input.js
 create mode 100644 packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/output.js

diff --git a/packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/input.js b/packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/input.js
new file mode 100644
index 000000000000..b3abe5f3bba8
--- /dev/null
+++ b/packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/input.js
@@ -0,0 +1,5 @@
+async () => do {
+  await 0
+  while (0) {}
+  0
+}
diff --git a/packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/output.js b/packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/output.js
new file mode 100644
index 000000000000..cd904d3f903d
--- /dev/null
+++ b/packages/babel-plugin-proposal-do-expressions/test/fixtures/do-expressions/regression-16293/output.js
@@ -0,0 +1,5 @@
+async () => await async function () {
+  await 0;
+  while (0) {}
+  return 0;
+}();
diff --git a/packages/babel-traverse/src/context.ts b/packages/babel-traverse/src/context.ts
index cd4f1ca8c694..c63bd6031a4b 100644
--- a/packages/babel-traverse/src/context.ts
+++ b/packages/babel-traverse/src/context.ts
@@ -118,9 +118,12 @@ export default class TraversalContext<S = unknown> {
 
     const visited = new WeakSet();
     let stop = false;
+    let visitIndex = 0;
 
     // visit the queue
-    for (const path of queue) {
+    for (; visitIndex < queue.length; ) {
+      const path = queue[visitIndex];
+      visitIndex++;
       path.resync();
 
       if (
@@ -154,9 +157,9 @@ export default class TraversalContext<S = unknown> {
       }
     }
 
-    // clear queue
-    for (const path of queue) {
-      path.popContext();
+    // pop contexts
+    for (let i = 0; i < visitIndex; i++) {
+      queue[i].popContext();
     }
 
     // clear queue

From 67dd9d660212e26886e3732e9a9f9efd3f483656 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hu=C3=A1ng=20J=C3=B9nli=C3=A0ng?= <jlhwung@gmail.com>
Date: Tue, 27 Feb 2024 21:03:35 -0500
Subject: [PATCH 2/2] add traverser behaviour test case

---
 packages/babel-traverse/test/traverse.js | 38 ++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/packages/babel-traverse/test/traverse.js b/packages/babel-traverse/test/traverse.js
index 2de1bb68b3f8..aa11e00b6d6d 100644
--- a/packages/babel-traverse/test/traverse.js
+++ b/packages/babel-traverse/test/traverse.js
@@ -314,6 +314,44 @@ describe("traverse", function () {
         ["EXIT", "./Bar"],
       ]);
     });
+    it("should preserve the context for those nodes that are not visited in sub-traversal", () => {
+      const code = `{ var first; function second() {} }`;
+      const ast = parse(code);
+      let contextLevel;
+      traverse(
+        ast,
+        {
+          enter(path) {
+            if (path.isFunctionDeclaration()) {
+              path.parentPath.traverse(
+                {
+                  enter(path) {
+                    if (path.isFunctionDeclaration()) {
+                      path.parentPath.traverse(
+                        {
+                          enter(path) {
+                            if (path.isVariableDeclaration()) path.stop();
+                          },
+                        },
+                        { level: 3 },
+                      );
+                      // the function declaration path should have state.level as 2
+                      // as it is defined within level 2 traversal and the node is
+                      // not visited in the next sub-traversal
+                      contextLevel = path.state.level;
+                    }
+                  },
+                },
+                { level: 2 },
+              );
+            }
+          },
+        },
+        undefined,
+        { level: 1 },
+      );
+      expect(contextLevel).toBe(2);
+    });
   });
   describe("path.stop()", () => {
     it("should stop the traversal when a grand child is stopped", () => {