chore(lambda): throw a relevant error message when asset is used across stacks

packages/@aws-cdk/aws-lambda/lib/code.ts

@@ -232,7 +232,7 @@ export class InlineCode extends Code {
  */
 export class AssetCode extends Code {
   public readonly isInline = false;
-  private asset?: s3_assets.Asset;
+  private assets: Record<string, s3_assets.Asset> = {};
 
   /**
    * @param path The path to the asset file or directory.
@@ -242,35 +242,43 @@ export class AssetCode extends Code {
   }
 
   public bind(scope: cdk.Construct): CodeConfig {
-    // If the same AssetCode is used multiple times, retain only the first instantiation.
-    if (!this.asset) {
-      this.asset = new s3_assets.Asset(scope, 'Code', {
+    const stackPath = cdk.Stack.of(scope).node.path; // use path instead of name to account for Stage.
+    let asset: s3_assets.Asset;
+    if (stackPath in this.assets) {
+      // If the same AssetCode is used multiple times, retain only the first instantiation.
+      asset = this.assets[stackPath];
+    } else {
+      asset = new s3_assets.Asset(scope, 'Code', {
         path: this.path,
         ...this.options,
       });
+      this.assets[stackPath] = asset;
     }
 
-    if (!this.asset.isZipArchive) {
+    if (!asset.isZipArchive) {
       throw new Error(`Asset must be a .zip file or a directory (${this.path})`);
     }
 
     return {
       s3Location: {
-        bucketName: this.asset.s3BucketName,
-        objectKey: this.asset.s3ObjectKey,
+        bucketName: asset.s3BucketName,
+        objectKey: asset.s3ObjectKey,
       },
     };
   }
 
   public bindToResource(resource: cdk.CfnResource, options: ResourceBindOptions = { }) {
-    if (!this.asset) {
+    const stackPath = cdk.Stack.of(resource).node.path;
+    const asset = this.assets[stackPath];
+
+    if (!asset) {
       throw new Error('bindToResource() must be called after bind()');
     }
 
     const resourceProperty = options.resourceProperty || 'Code';
 
     // https://github.com/aws/aws-cdk/issues/1432
-    this.asset.addResourceMetadata(resource, resourceProperty);
+    asset.addResourceMetadata(resource, resourceProperty);
   }
 }
 

packages/@aws-cdk/aws-lambda/test/code.test.ts

@@ -77,6 +77,34 @@ describe('code', () => {
         },
       }, ResourcePart.CompleteDefinition);
     });
+
+    test('can be used in multiple stacks', () => {
+      // GIVEN
+      const app = new cdk.App();
+      const stack1 = new cdk.Stack(app, 'Stack1');
+      const stack2 = new cdk.Stack(app, 'Stack2');
+      const asset = lambda.Code.fromAsset(path.join(__dirname, 'my-lambda-handler'));
+
+      // WHEN
+      new lambda.Function(stack1, 'Func', {
+        code: asset,
+        runtime: lambda.Runtime.NODEJS_12_X,
+        handler: 'foom',
+      });
+      new lambda.Function(stack2, 'Func', {
+        code: asset,
+        runtime: lambda.Runtime.NODEJS_12_X,
+        handler: 'foom',
+      });
+
+      // THEN
+      const assembly = app.synth();
+      const synthesized1 = assembly.getStackArtifact(stack1.artifactId);
+      const synthesized2 = assembly.getStackArtifact(stack2.artifactId);
+
+      expect(synthesized1.assets.length).toEqual(1);
+      expect(synthesized2.assets.length).toEqual(1);
+    });
   });
 
   describe('lambda.Code.fromCfnParameters', () => {