fix(cfn-include): allow Conditions to reference Mappings in their def…

…initions (#10105)

Fixes #10099

----

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

packages/@aws-cdk/cloudformation-include/lib/cfn-include.ts

@@ -444,7 +444,9 @@ export class CfnInclude extends core.CfnElement {
             ? self.getOrCreateCondition(cName)
             : undefined;
         },
-        findMapping() { throw new Error('Using FindInMap in Condition definitions is not allowed'); },
+        findMapping(mappingName: string): core.CfnMapping | undefined {
+          return self.mappings[mappingName];
+        },
       },
       context: cfn_parse.CfnParsingContext.CONDITIONS,
       parameters: this.parametersToReplace,

packages/@aws-cdk/cloudformation-include/test/test-templates/condition-using-mapping.json

@@ -0,0 +1,17 @@
+{
+  "Conditions": {
+    "AlwaysTrue": {
+      "Fn::Equals": [
+        { "Fn::FindInMap": ["Mapping01", "Key01", "Name"] },
+        "Value01"
+      ]
+    }
+  },
+  "Mappings" : {
+    "Mapping01" : {
+      "Key01" : {
+        "Name" : "Value01"
+      }
+    }
+  }
+}

packages/@aws-cdk/cloudformation-include/test/valid-templates.test.ts

@@ -352,6 +352,14 @@ describe('CDK Include', () => {
     );
   });
 
+  test('allows Conditions to reference Mappings', () => {
+    includeTestTemplate(stack, 'condition-using-mapping.json');
+
+    expect(stack).toMatchTemplate(
+      loadTestFileToJsObject('condition-using-mapping.json'),
+    );
+  });
+
   test('correctly change references to Conditions when renaming them', () => {
     const cfnTemplate = includeTestTemplate(stack, 'condition-same-name-as-resource.json');
     const alwaysFalse = cfnTemplate.getCondition('AlwaysFalse');