From 301a1fc7631bb862f003cc2ebfab37a42e5fdbc5 Mon Sep 17 00:00:00 2001
From: Hendiadyoin1 <leon.a@serenityos.org>
Date: Thu, 11 Apr 2024 00:25:54 +0200
Subject: [PATCH] LibJS: Propagate finalizers into nested try-catch blocks
 without them

---
 .../Libraries/LibJS/Bytecode/ASTCodegen.cpp   |  9 +++-
 Userland/Libraries/LibJS/Bytecode/Generator.h |  2 +
 .../LibJS/Tests/try-catch-finally-nested.js   | 50 +++++++++++++++++++
 3 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
index 476dbbc07bb..cd997b3be15 100644
--- a/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
+++ b/Userland/Libraries/LibJS/Bytecode/ASTCodegen.cpp
@@ -2510,8 +2510,13 @@ Bytecode::CodeGenerationErrorOr<Optional<Bytecode::Operand>> TryStatement::gener
     if (m_finalizer)
         generator.end_boundary(Bytecode::Generator::BlockBoundaryType::ReturnToFinally);
     if (m_handler) {
-        if (!m_finalizer)
-            unwind_context.emplace(generator, OptionalNone());
+        if (!m_finalizer) {
+            auto const* parent_unwind_context = generator.current_unwind_context();
+            if (parent_unwind_context)
+                unwind_context.emplace(generator, parent_unwind_context->finalizer());
+            else
+                unwind_context.emplace(generator, OptionalNone());
+        }
         unwind_context->set_handler(handler_target.value());
     }
 
diff --git a/Userland/Libraries/LibJS/Bytecode/Generator.h b/Userland/Libraries/LibJS/Bytecode/Generator.h
index 1b9b81ae69c..b1968961c14 100644
--- a/Userland/Libraries/LibJS/Bytecode/Generator.h
+++ b/Userland/Libraries/LibJS/Bytecode/Generator.h
@@ -276,6 +276,8 @@ public:
         return Operand(Operand::Type::Constant, m_constants.size() - 1);
     }
 
+    UnwindContext const* current_unwind_context() const { return m_current_unwind_context; }
+
 private:
     VM& m_vm;
 
diff --git a/Userland/Libraries/LibJS/Tests/try-catch-finally-nested.js b/Userland/Libraries/LibJS/Tests/try-catch-finally-nested.js
index da9ad2d438a..7614b054838 100644
--- a/Userland/Libraries/LibJS/Tests/try-catch-finally-nested.js
+++ b/Userland/Libraries/LibJS/Tests/try-catch-finally-nested.js
@@ -53,3 +53,53 @@ test("Nested try/catch/finally with exceptions", () => {
     expect(level3CatchHasBeenExecuted).toBeTrue();
     expect(level3FinallyHasBeenExecuted).toBeTrue();
 });
+
+test("Nested try/catch/finally with return in inner context", () => {
+    success = false;
+    (() => {
+        try {
+            try {
+                return;
+            } catch (e) {
+                expect().fail();
+            }
+        } finally {
+            success = true;
+        }
+        expect().fail();
+    })();
+    expect(success).toBeTrue();
+});
+
+test("Deeply nested try/catch/finally with return in inner context", () => {
+    success = 0;
+    (() => {
+        try {
+            try {
+                try {
+                    try {
+                        try {
+                            return;
+                        } catch (e) {
+                            expect().fail();
+                        } finally {
+                            success += 4;
+                        }
+                    } catch (e) {
+                        expect().fail();
+                    }
+                } catch (e) {
+                    expect().fail();
+                } finally {
+                    success += 2;
+                }
+            } catch (e) {
+                expect().fail();
+            }
+        } finally {
+            success += 1;
+        }
+        expect().fail();
+    })();
+    expect(success).toBe(7);
+});