chore(lambda): hide warning if skipPermissions is set (aws#30060)

### Issue aws#29887

Closes aws#29887

### Reason for this change

If an user imports a lambda and wants to add permissions a warning is show. This warning should be skippable with the skipPermissions flag.

### Description of how you validated changes

Unit tests for checking if the warning is shown/not shown depending on the value of `skipPermissions` are added.

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/aws-cdk-lib/aws-lambda/lib/function-base.ts

@@ -344,7 +344,9 @@ export abstract class FunctionBase extends Resource implements IFunction, ec2.IC
    */
   public addPermission(id: string, permission: Permission) {
     if (!this.canCreatePermissions) {
-      Annotations.of(this).addWarningV2('UnclearLambdaEnvironment', `addPermission() has no effect on a Lambda Function with region=${this.env.region}, account=${this.env.account}, in a Stack with region=${Stack.of(this).region}, account=${Stack.of(this).account}. Suppress this warning if this is is intentional, or pass sameEnvironment=true to fromFunctionAttributes() if you would like to add the permissions.`);
+      if (!this._skipPermissions) {
+        Annotations.of(this).addWarningV2('UnclearLambdaEnvironment', `addPermission() has no effect on a Lambda Function with region=${this.env.region}, account=${this.env.account}, in a Stack with region=${Stack.of(this).region}, account=${Stack.of(this).account}. Suppress this warning if this is is intentional, or pass sameEnvironment=true to fromFunctionAttributes() if you would like to add the permissions.`);
+      }
       return;
     }
 

packages/aws-cdk-lib/aws-lambda/test/function.test.ts

@@ -7,6 +7,7 @@ import { ProfilingGroup } from '../../aws-codeguruprofiler';
 import * as ec2 from '../../aws-ec2';
 import * as efs from '../../aws-efs';
 import * as iam from '../../aws-iam';
+import { AccountPrincipal } from '../../aws-iam';
 import * as kms from '../../aws-kms';
 import * as logs from '../../aws-logs';
 import * as s3 from '../../aws-s3';
@@ -15,6 +16,7 @@ import * as sns from '../../aws-sns';
 import * as sqs from '../../aws-sqs';
 import * as cdk from '../../core';
 import { Aspects, Lazy, Size } from '../../core';
+import { getWarnings } from '../../core/test/util';
 import * as cxapi from '../../cx-api';
 import * as lambda from '../lib';
 import { AdotLambdaLayerJavaSdkVersion } from '../lib/adot-layers';
@@ -223,6 +225,55 @@ describe('function', () => {
       fn.addPermission('S4', { principal: new iam.OrganizationPrincipal('my:org') });
     });
 
+    test('does not show warning if skipPermissions is set', () => {
+      const app = new cdk.App();
+      const stack = new cdk.Stack(app);
+      const imported = lambda.Function.fromFunctionAttributes(stack, 'Imported', {
+        functionArn: 'arn:aws:lambda:us-west-2:123456789012:function:my-function',
+        skipPermissions: true,
+      });
+      imported.addPermission('Permission', {
+        action: 'lambda:InvokeFunction',
+        principal: new AccountPrincipal('123456789010'),
+      });
+
+      expect(getWarnings(app.synth()).length).toBe(0);
+    });
+
+    test('shows warning if skipPermissions is not set', () => {
+      const app = new cdk.App();
+      const stack = new cdk.Stack(app);
+      const imported = lambda.Function.fromFunctionAttributes(stack, 'Imported', {
+        functionArn: 'arn:aws:lambda:us-west-2:123456789012:function:my-function',
+      });
+      imported.addPermission('Permission', {
+        action: 'lambda:InvokeFunction',
+        principal: new AccountPrincipal('123456789010'),
+      });
+
+      expect(getWarnings(app.synth())).toEqual([
+        {
+          message: {
+            'Fn::Join': [
+              '',
+              [
+                'addPermission() has no effect on a Lambda Function with region=us-west-2, account=123456789012, in a Stack with region=',
+                {
+                  Ref: 'AWS::Region',
+                },
+                ', account=',
+                {
+                  Ref: 'AWS::AccountId',
+                },
+                '. Suppress this warning if this is is intentional, or pass sameEnvironment=true to fromFunctionAttributes() if you would like to add the permissions. [ack: UnclearLambdaEnvironment]',
+              ],
+            ],
+          },
+          path: '/Default/Imported',
+        },
+      ]);
+    });
+
     test('applies source account/ARN conditions if the principal has conditions', () => {
       const stack = new cdk.Stack();
       const fn = newTestLambda(stack);