From 77d6bb2d8cbc6f9d56cebe1616f36324da039d8d Mon Sep 17 00:00:00 2001
From: KernelDeimos <eric.alex.dube@gmail.com>
Date: Wed, 29 Jan 2025 10:31:58 -0500
Subject: [PATCH] dev: always select highest version of the specified language

---
 .../src/modules/puterexec/Judge0Service.js    |  5 ++-
 src/backend/src/util/versionutil.js           | 33 +++++++++++++++++++
 src/backend/src/util/versionutil.test.js      | 18 ++++++++++
 3 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 src/backend/src/util/versionutil.js
 create mode 100644 src/backend/src/util/versionutil.test.js

diff --git a/src/backend/src/modules/puterexec/Judge0Service.js b/src/backend/src/modules/puterexec/Judge0Service.js
index 6c0d9fd57..a7d067225 100644
--- a/src/backend/src/modules/puterexec/Judge0Service.js
+++ b/src/backend/src/modules/puterexec/Judge0Service.js
@@ -2,6 +2,7 @@ const putility = require("@heyputer/putility");
 const BaseService = require("../../services/BaseService");
 const { Judge0Client } = require("./Judge0Client");
 const { Context } = require("../../util/context");
+const { find_highest_version } = require("../../util/versionutil");
 
 class Judge0Service extends BaseService {
     _construct () {
@@ -46,7 +47,9 @@ class Judge0Service extends BaseService {
                     return lang.judge0_id;
                 }
             }
-            let lang = this.languages.find((lang) => lang.language === runtime);
+            const matchingLangs = this.languages.filter((lang) => lang.language === runtime);
+            const lang = find_highest_version(matchingLangs);
+
             if ( lang ) {
                 return lang.judge0_id;
             }
diff --git a/src/backend/src/util/versionutil.js b/src/backend/src/util/versionutil.js
new file mode 100644
index 000000000..c86f106d7
--- /dev/null
+++ b/src/backend/src/util/versionutil.js
@@ -0,0 +1,33 @@
+/**
+ * Select the object with the highest version.
+ * Objects are of the form:
+ *   { version: '1.2.0' }
+ * 
+ * Semver is assumed.
+ * 
+ * @param {*} objects 
+ */
+const find_highest_version = (objects) => {
+    let highest = [0,0,0];
+    let highest_obj = null;
+
+    for ( const obj of objects ) {
+        const parts = obj.version.split('.');
+        for ( let i = 0; i < 3; i++ ) {
+            const part = parseInt(parts[i]);
+            if ( part > highest[i] ) {
+                highest = parts;
+                highest_obj = obj;
+                break;
+            } else if ( part < highest[i] ) {
+                break;
+            }1
+        }
+    }
+
+    return highest_obj;
+};
+
+module.exports = {
+    find_highest_version,
+};
diff --git a/src/backend/src/util/versionutil.test.js b/src/backend/src/util/versionutil.test.js
new file mode 100644
index 000000000..b8ac38b10
--- /dev/null
+++ b/src/backend/src/util/versionutil.test.js
@@ -0,0 +1,18 @@
+const { expect } = require('chai');
+
+describe('versionutil', () => {
+    it('works', () => {
+        const objects = [
+            { version: '1.2.0' },
+            { version: '3.0.2' },
+            { version: '1.2.1' },
+            { version: '1.2.0' },
+            { version: '3.1.0', h: true },
+            { version: '1.2.2' },
+        ];
+
+        const { find_highest_version } = require('./versionutil');
+        const highest_object = find_highest_version(objects);
+        expect(highest_object).to.deep.equal({ version: '3.1.0', h: true });
+    });
+});
\ No newline at end of file