fix(cli): cross account asset upload no longer works

packages/aws-cdk/lib/util/asset-publishing.ts

@@ -39,6 +39,10 @@ class PublishingAws implements cdk_assets.IAws {
     private readonly targetEnv: cxapi.Environment) {
   }
 
+  public async discoverPartition(): Promise<string> {
+    return (await this.aws.baseCredentialsPartition(this.targetEnv, Mode.ForWriting)) ?? 'aws';
+  }
+
   public async discoverDefaultRegion(): Promise<string> {
     return this.targetEnv.region;
   }

packages/cdk-assets/bin/publish.ts

@@ -86,6 +86,10 @@ class DefaultAwsClient implements IAws {
     return new this.AWS.ECR(await this.awsOptions(options));
   }
 
+  public async discoverPartition(): Promise<string> {
+    return (await this.discoverCurrentAccount()).partition;
+  }
+
   public async discoverDefaultRegion(): Promise<string> {
     return this.AWS.config.region || 'us-east-1';
   }

packages/cdk-assets/lib/aws.ts

@@ -4,6 +4,7 @@ import * as AWS from 'aws-sdk';
  * AWS SDK operations required by Asset Publishing
  */
 export interface IAws {
+  discoverPartition(): Promise<string>;
   discoverDefaultRegion(): Promise<string>;
   discoverCurrentAccount(): Promise<Account>;
 

packages/cdk-assets/lib/private/placeholders.ts

@@ -8,6 +8,12 @@ import { IAws } from '../aws';
  * (they're nominally independent tools).
  */
 export async function replaceAwsPlaceholders<A extends { region?: string }>(object: A, aws: IAws): Promise<A> {
+  let partition = async () => {
+    const p = await aws.discoverPartition();
+    partition = () => Promise.resolve(p);
+    return p;
+  };
+
   let account = async () => {
     const a = await aws.discoverCurrentAccount();
     account = () => Promise.resolve(a);
@@ -22,7 +28,7 @@ export async function replaceAwsPlaceholders<A extends { region?: string }>(obje
       return (await account()).accountId;
     },
     async partition() {
-      return (await account()).partition;
+      return partition();
     },
   });
 }

packages/cdk-assets/test/mock-aws.ts

@@ -18,6 +18,7 @@ export function mockAws() {
   return {
     mockEcr,
     mockS3,
+    discoverPartition: jest.fn(() => Promise.resolve('swa')),
     discoverCurrentAccount: jest.fn(() => Promise.resolve({ accountId: 'current_account', partition: 'swa' })),
     discoverDefaultRegion: jest.fn(() => Promise.resolve('current_region')),
     ecrClient: jest.fn(() => Promise.resolve(mockEcr)),