fix: 🐛 updated detectCircularDependency in DependencyGraph to return circular dependencies starting from the first node

Signed-off-by: Marley Powell <marley.powell@exclaimer.com>

packages/backend-app-api/src/lib/DependencyGraph.test.ts

@@ -66,6 +66,17 @@ describe('DependencyGraph', () => {
       ).toEqual(['1', '2', '1']);
     });
 
+    it('should detect a circular dep starting from the first node', async () => {
+      expect(
+        DependencyGraph.fromMap({
+          1: { provides: ['a'], consumes: ['b'] },
+          2: { provides: ['b'], consumes: ['c'] },
+          3: { provides: ['c'], consumes: ['d'] },
+          4: { provides: ['d'], consumes: ['a'] },
+        }).detectCircularDependency(),
+      ).toEqual(['1', '2', '3', '4', '1']);
+    });
+
     it('should detect a larger distant circular dep', async () => {
       expect(
         DependencyGraph.fromMap({
@@ -74,7 +85,7 @@ describe('DependencyGraph', () => {
           3: { provides: ['c'], consumes: ['b'] },
           4: { provides: ['d', 'e'], consumes: ['c', 'a'] },
         }).detectCircularDependency(),
-      ).toEqual(['2', '3', '4', '2']);
+      ).toEqual(['2', '4', '3', '2']);
     });
   });
 

packages/backend-app-api/src/lib/DependencyGraph.ts

@@ -108,16 +108,16 @@ export class DependencyGraph<T> {
           continue;
         }
         visited.add(node);
-        for (const produced of node.provides) {
-          const consumerNodes = this.#nodes.filter(other =>
-            other.consumes.has(produced),
+        for (const consumed of node.consumes) {
+          const providerNodes = this.#nodes.filter(other =>
+            other.provides.has(consumed),
           );
-          for (const consumer of consumerNodes) {
-            if (consumer === startNode) {
+          for (const provider of providerNodes) {
+            if (provider === startNode) {
               return [...path, startNode.value];
             }
-            if (!visited.has(consumer)) {
-              stack.push([consumer, [...path, consumer.value]]);
+            if (!visited.has(provider)) {
+              stack.push([provider, [...path, provider.value]]);
             }
           }
         }