fix(ssm): StringParameter.fromSecureStringParameterAttributes not working without version (#22618)

It is possible to omit the `version` of an SSM SecureString parameter.

When omitted, the reference generated by CDK results in a ValidationError when applying the changes.

e.g.

```
Error [ValidationError]: Incorrect format is used in the following SSM reference: [{{resolve:ssm-secure:/some/parameter:}}]
```

Related to #18729
Replaces #22311

----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
	* [x] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

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

Author: mrgrain

packages/@aws-cdk/aws-ssm/README.md

@@ -18,7 +18,31 @@ This module is part of the [AWS Cloud Development Kit](https://github.com/aws/aw
 You can reference existing SSM Parameter Store values that you want to use in
 your CDK app by using `ssm.StringParameter.fromStringParameterAttributes`:
 
-[using SSM parameter](test/integ.parameter-store-string.lit.ts)
+```ts
+// Retrieve the latest value of the non-secret parameter
+// with name "/My/String/Parameter".
+const stringValue = ssm.StringParameter.fromStringParameterAttributes(this, 'MyValue', {
+  parameterName: '/My/Public/Parameter',
+  // 'version' can be specified but is optional.
+}).stringValue;
+const stringValueVersionFromToken = ssm.StringParameter.fromStringParameterAttributes(this, 'MyValueVersionFromToken', {
+  parameterName: '/My/Public/Parameter',
+  // parameter version from token
+  version: parameterVersion,
+}).stringValue;
+
+// Retrieve a specific version of the secret (SecureString) parameter.
+// 'version' is always required.
+const secretValue = ssm.StringParameter.fromSecureStringParameterAttributes(this, 'MySecureValue', {
+  parameterName: '/My/Secret/Parameter',
+  version: 5,
+});
+const secretValueVersionFromToken = ssm.StringParameter.fromSecureStringParameterAttributes(this, 'MySecureValueVersionFromToken', {
+  parameterName: '/My/Secret/Parameter',
+  // parameter version from token
+  version: parameterVersion,
+});
+```
 
 You can also reference an existing SSM Parameter Store value that matches an
 [AWS specific parameter type](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/parameters-section-structure.html#aws-specific-parameter-types):

packages/@aws-cdk/aws-ssm/lib/parameter.ts

@@ -492,7 +492,10 @@ export class StringParameter extends ParameterBase implements IStringParameter {
    */
   public static fromSecureStringParameterAttributes(scope: Construct, id: string, attrs: SecureStringParameterAttributes): IStringParameter {
     const version = attrs.version ? Tokenization.stringifyNumber(attrs.version) : '';
-    const stringValue = new CfnDynamicReference(CfnDynamicReferenceService.SSM_SECURE, `${attrs.parameterName}:${version}`).toString();
+    const stringValue = new CfnDynamicReference(
+      CfnDynamicReferenceService.SSM_SECURE,
+      version ? `${attrs.parameterName}:${version}` : attrs.parameterName,
+    ).toString();
 
     class Import extends ParameterBase {
       public readonly parameterName = attrs.parameterName;

packages/@aws-cdk/aws-ssm/test/integ.parameter-store-string.lit.ts renamed to packages/@aws-cdk/aws-ssm/test/integ.parameter-store-string.ts

@@ -1,14 +1,26 @@
-/// !cdk-integ *
 import * as cdk from '@aws-cdk/core';
+import * as integ from '@aws-cdk/integ-tests';
 import * as ssm from '../lib';
 
+const SECURE_PARAM_NAME = '/My/Secret/Parameter';
+
 class CreatingStack extends cdk.Stack {
   constructor(scope: cdk.App, id: string) {
     super(scope, id);
 
     new ssm.StringParameter(this, 'String', {
       parameterName: '/My/Public/Parameter',
-      stringValue: 'abcdef',
+      stringValue: 'Abc123',
+    });
+
+    new integ.AwsApiCall(this, 'SecureParam', {
+      service: 'SSM',
+      api: 'putParameter',
+      parameters: {
+        Name: SECURE_PARAM_NAME,
+        Type: 'SecureString',
+        Value: 'Abc123',
+      },
     });
   }
 }
@@ -24,7 +36,6 @@ class UsingStack extends cdk.Stack {
       default: 1,
     }).valueAsNumber;
 
-    /// !show
     // Retrieve the latest value of the non-secret parameter
     // with name "/My/String/Parameter".
     const stringValue = ssm.StringParameter.fromStringParameterAttributes(this, 'MyValue', {
@@ -38,33 +49,54 @@ class UsingStack extends cdk.Stack {
     }).stringValue;
 
     // Retrieve a specific version of the secret (SecureString) parameter.
-    // 'version' is always required.
     const secretValue = ssm.StringParameter.fromSecureStringParameterAttributes(this, 'MySecureValue', {
       parameterName: '/My/Secret/Parameter',
-      version: 5,
-    });
+    }).stringValue;
+    const secretValueVersion = ssm.StringParameter.fromSecureStringParameterAttributes(this, 'MySecureValueVersion', {
+      parameterName: '/My/Secret/Parameter',
+      version: 1,
+    }).stringValue;
     const secretValueVersionFromToken = ssm.StringParameter.fromSecureStringParameterAttributes(this, 'MySecureValueVersionFromToken', {
       parameterName: '/My/Secret/Parameter',
       // parameter version from token
       version: parameterVersion,
-    });
-
-    /// !hide
-
-    new cdk.CfnResource(this, 'Dummy', { type: 'AWS::SNS::Topic' });
-    new cdk.CfnOutput(this, 'TheValue', { value: stringValue });
-    new cdk.CfnOutput(this, 'TheValueVersionFromToken', { value: stringValueVersionFromToken });
+    }).stringValue;
 
-    // Cannot be provisioned so cannot be actually used
-    Array.isArray(secretValue);
-    Array.isArray(secretValueVersionFromToken);
+    const user = new cdk.CfnResource(this, 'DummyResourceUsingStringParameters', {
+      type: 'AWS::IAM::User',
+      properties: {
+        LoginProfile: {
+          Password: cdk.Fn.join('-', [
+            stringValue,
+            stringValueVersionFromToken,
+            secretValue,
+            secretValueVersion,
+            secretValueVersionFromToken,
+          ]),
+        },
+      },
+    });
+    user.applyRemovalPolicy(cdk.RemovalPolicy.DESTROY);
   }
 }
 
 const app = new cdk.App();
 
 const creating = new CreatingStack(app, 'sspms-creating');
+
 const using = new UsingStack(app, 'sspms-using');
 using.addDependency(creating);
 
+const cleanup = new cdk.Stack(app, 'sspms-cleanup');
+cleanup.addDependency(using);
+
+const integTest = new integ.IntegTest(app, 'SSMParameterStoreTest', {
+  assertionStack: cleanup,
+  testCases: [using],
+});
+
+integTest.assertions.awsApiCall('SSM', 'deleteParameter', {
+  Name: SECURE_PARAM_NAME,
+});
+
 app.synth();