fix(core): make get() throw for implicitly request-scoped trees

Treat non-static dependency trees as scoped in get(); instruct consumers to use resolve().\n\nAdds focused tests under NestApplicationContext spec to cover implicit request scope via enhancers.\n\nCloses #15836.

Author: JoeNutt

packages/core/injector/abstract-instance-resolver.ts

@@ -29,7 +29,8 @@ export abstract class AbstractInstanceResolver {
     const pluckInstance = ({ wrapperRef }: InstanceLink) => {
       if (
         wrapperRef.scope === Scope.REQUEST ||
-        wrapperRef.scope === Scope.TRANSIENT
+        wrapperRef.scope === Scope.TRANSIENT ||
+        !wrapperRef.isDependencyTreeStatic()
       ) {
         throw new InvalidClassScopeException(typeOrToken);
       }

packages/core/test/nest-application-context.spec.ts

@@ -1,4 +1,4 @@
-import { InjectionToken, Provider, Scope } from '@nestjs/common';
+import { InjectionToken, Provider, Scope, Injectable } from '@nestjs/common';
 import { expect } from 'chai';
 import * as sinon from 'sinon';
 import { setTimeout } from 'timers/promises';
@@ -375,4 +375,64 @@ describe('NestApplicationContext', () => {
       });
     });
   });
+
+  describe('implicit request scope via enhancers', () => {
+    it('get() should throw when dependency tree is not static (request-scoped enhancer attached)', async () => {
+      class Host {}
+      @Injectable({ scope: Scope.REQUEST })
+      class ReqScopedPipe {}
+
+      const nestContainer = new NestContainer();
+      const injector = new Injector();
+      const instanceLoader = new InstanceLoader(
+        nestContainer,
+        injector,
+        new GraphInspector(nestContainer),
+      );
+      const { moduleRef } = (await nestContainer.addModule(class T {}, []))!;
+
+      // Register Host as a controller (matches real-world controller case)
+      nestContainer.addController(Host, moduleRef.token);
+
+      // Register a request-scoped injectable and attach it as an enhancer to Host
+      // This simulates a method-level pipe/guard/interceptor making Host implicitly request-scoped
+      nestContainer.addInjectable(ReqScopedPipe, moduleRef.token, 'pipe', Host);
+
+      const modules = nestContainer.getModules();
+      await instanceLoader.createInstancesOfDependencies(modules);
+
+      const appCtx = new NestApplicationContext(nestContainer);
+
+      // With a non-static dependency tree, get() should refuse and instruct to use resolve()
+      expect(() => appCtx.get(Host)).to.throw();
+    });
+
+    it('resolve() should instantiate when dependency tree is not static (request-scoped enhancer attached)', async () => {
+      class Host {}
+      @Injectable({ scope: Scope.REQUEST })
+      class ReqScopedPipe {}
+
+      const nestContainer = new NestContainer();
+      const injector = new Injector();
+      const instanceLoader = new InstanceLoader(
+        nestContainer,
+        injector,
+        new GraphInspector(nestContainer),
+      );
+      const { moduleRef } = (await nestContainer.addModule(class T {}, []))!;
+
+      // Register Host as a controller
+      nestContainer.addController(Host, moduleRef.token);
+
+      nestContainer.addInjectable(ReqScopedPipe, moduleRef.token, 'pipe', Host);
+
+      const modules = nestContainer.getModules();
+      await instanceLoader.createInstancesOfDependencies(modules);
+
+      const appCtx = new NestApplicationContext(nestContainer);
+
+      const instance = await appCtx.resolve(Host);
+      expect(instance).instanceOf(Host);
+    });
+  });
 });