Ignore external packages in action sorter

Author: veehz

.github/actions/src/info/__tests__/sorter.test.ts

@@ -47,6 +47,25 @@ describe(topoSortPackages, () => {
     ]);
   });
 
+  test('Ignores external Source Academy dependencies', () => {
+    const result = topoSortPackages({
+      '@sourceacademy/0': {
+        type: null,
+        hasChanges: false,
+        directory: '/',
+        package: {
+          name: '@sourceacademy/0',
+          devDependencies: {},
+          dependencies: {
+            '@sourceacademy/external': '^1.0.0'
+          }
+        }
+      }
+    });
+
+    expect(result).toEqual(['@sourceacademy/0']);
+  });
+
   test('With a cycle', () => {
     const func = () => topoSortPackages({
       '@sourceacademy/0': {

.github/actions/src/info/sorter.ts

@@ -27,16 +27,9 @@ export function topoSortPackages(packages: Record<string, RawPackageRecord>) {
       keys.push(...Object.keys(devDependencies));
     }
 
-    for (const name of keys) {
-      if (name.startsWith('@sourceacademy')) {
-        if (!(name in indegrees)) {
-          indegrees[name] = 1;
-        } else {
-          indegrees[name]++;
-        }
-
-        neighbours[packageName].push(name);
-      }
+    for (const name of keys.filter(k => k in packages)) {
+      indegrees[name] = (indegrees[name] ?? 0) + 1;
+      neighbours[packageName].push(name);
     }
   }