From 8cb7e2baf227ee1fc453a2fec1d5e7cf3365a52d Mon Sep 17 00:00:00 2001
From: Tom Wright <tom.suffern.wright@gmail.com>
Date: Tue, 26 Sep 2023 17:16:53 +1000
Subject: [PATCH] feat: resolve Fn::ImportValue

---
 .../aws-cdk/lib/api/evaluate-cloudformation-template.ts  | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/packages/aws-cdk/lib/api/evaluate-cloudformation-template.ts b/packages/aws-cdk/lib/api/evaluate-cloudformation-template.ts
index 0a4446621e11c..8d56646852d10 100644
--- a/packages/aws-cdk/lib/api/evaluate-cloudformation-template.ts
+++ b/packages/aws-cdk/lib/api/evaluate-cloudformation-template.ts
@@ -144,6 +144,7 @@ export class EvaluateCloudFormationTemplate {
       partition: this.partition,
       urlSuffix: this.urlSuffix,
       listStackResources: listNestedStackResources,
+      lookupExport: this.lookupExport,
     });
   }
 
@@ -249,6 +250,14 @@ export class EvaluateCloudFormationTemplate {
           }
         });
       }
+
+      async 'Fn::ImportValue'(name: string): Promise<string> {
+        const exported = await self.lookupExport.lookupExport(name);
+        if (!exported.Value) {
+          throw new CfnEvaluationException(`Export '${name}' exists without a value`);
+        }
+        return exported.Value;
+      }
     }
 
     if (cfnExpression == null) {