From 9f82165fd75da8c79c526c8cc44b99264733f00e Mon Sep 17 00:00:00 2001
From: NhatMinh0208 <minhkhicon2468@gmail.com>
Date: Sun, 18 Feb 2024 17:15:28 +0800
Subject: [PATCH] CSE Machine: Fix environment reset instruction insertion
 (#1542)

* fix environment reset instruction insertion

* Update nodejs.yml

* remove unneccesary semiclolon in .github/workflows/nodejs.yml

Co-authored-by: Richard Dominick <34370238+RichDom2185@users.noreply.github.com>

---------

Co-authored-by: Richard Dominick <34370238+RichDom2185@users.noreply.github.com>
---
 .../__tests__/__snapshots__/cse-machine.ts.snap     | 13 +++++++++++++
 src/cse-machine/__tests__/cse-machine.ts            |  9 +++++++++
 src/cse-machine/interpreter.ts                      |  2 +-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/cse-machine/__tests__/__snapshots__/cse-machine.ts.snap b/src/cse-machine/__tests__/__snapshots__/cse-machine.ts.snap
index 9fd807f01..4a58dff15 100644
--- a/src/cse-machine/__tests__/__snapshots__/cse-machine.ts.snap
+++ b/src/cse-machine/__tests__/__snapshots__/cse-machine.ts.snap
@@ -97,6 +97,19 @@ fact(5);",
 }
 `;
 
+exports[`Environment reset is inserted when only instructions are in control stack: expectResult 1`] = `
+Object {
+  "alertResult": Array [],
+  "code": "const a = (v => v)(0);",
+  "displayResult": Array [],
+  "numErrors": 0,
+  "parsedErrors": "",
+  "result": undefined,
+  "resultStatus": "finished",
+  "visualiseListResult": Array [],
+}
+`;
+
 exports[`Imports are properly handled: expectResult 1`] = `
 Object {
   "alertResult": Array [],
diff --git a/src/cse-machine/__tests__/cse-machine.ts b/src/cse-machine/__tests__/cse-machine.ts
index 0f55abbb0..4cab099c4 100644
--- a/src/cse-machine/__tests__/cse-machine.ts
+++ b/src/cse-machine/__tests__/cse-machine.ts
@@ -460,3 +460,12 @@ test('Breaks, continues and returns are detected properly inside loops', () => {
     optionEC3
   ).toMatchInlineSnapshot(`3`)
 })
+
+test('Environment reset is inserted when only instructions are in control stack', () => {
+  return expectResult(
+    stripIndent`
+    const a = (v => v)(0);
+    `,
+    optionEC3
+  ).toMatchInlineSnapshot(`undefined`)
+})
diff --git a/src/cse-machine/interpreter.ts b/src/cse-machine/interpreter.ts
index 50f6480b8..56fce22f2 100644
--- a/src/cse-machine/interpreter.ts
+++ b/src/cse-machine/interpreter.ts
@@ -827,7 +827,7 @@ const cmdEvaluators: { [type: string]: CmdEvaluator } = {
       if (
         next &&
         !(isInstr(next) && next.instrType === InstrType.ENVIRONMENT) &&
-        control.some(isNode)
+        !control.isEmpty()
       ) {
         control.push(instr.envInstr(currentEnvironment(context), command.srcNode))
       }