fix(core) circular dependency when calculating distance of modules

Author: kamilmysliwiec

packages/core/injector/module.ts

@@ -120,11 +120,13 @@ export class Module {
     return this._distance;
   }
 
-  set distance(distance: number) {
+  public updateDistance(distance: number, stack: Module[]) {
     this._distance = distance;
     Array.from(this._imports)
-      .filter(module => module && !module.imports.has(this))
-      .forEach(module => (module.distance = distance + 1));
+      .filter(module => module && !stack.includes(this))
+      .forEach(module =>
+        module.updateDistance(distance + 1, stack.concat(this)),
+      );
   }
 
   public addCoreProviders(container: NestContainer) {
@@ -413,10 +415,9 @@ export class Module {
 
   public addRelatedModule(module: Module) {
     this._imports.add(module);
-    module.distance =
-      this._distance + 1 > module._distance
-        ? this._distance + 1
-        : module._distance;
+    if (this._distance + 1 > module._distance) {
+      module.updateDistance(this._distance + 1, [this]);
+    }
   }
 
   public replace(toReplace: string | symbol | Type<any>, options: any) {

packages/core/test/injector/module.spec.ts

@@ -499,7 +499,7 @@ describe('Module', () => {
       moduleC = new Module(ModuleC as any, [], container);
     });
 
-    it('should get "distance" correct', () => {
+    it('should calculate "distance" properly', () => {
       moduleA.addRelatedModule(moduleB);
       moduleC.addRelatedModule(moduleB);
       moduleA.addRelatedModule(moduleC);
@@ -509,11 +509,16 @@ describe('Module', () => {
       expect(moduleC.distance).to.be.equal(1);
     });
 
-    it('should don`t throw exception when circular dependency', () => {
+    it('should not throw an exception when circular dependency occurs', () => {
       expect(() => {
         moduleA.addRelatedModule(moduleB);
         moduleB.addRelatedModule(moduleA);
       }).to.not.throw;
+      expect(() => {
+        moduleA.addRelatedModule(moduleB);
+        moduleB.addRelatedModule(moduleC);
+        moduleC.addRelatedModule(moduleA);
+      }).to.not.throw;
     });
   });
 });