aws-cdk-lib(core): App Inherits From Stage, But Doesn't Allow Setting Region

[shellscape]

Describe the bug

I believe there's a fundamental "miss" in the code for App. App inherits from Stage yet does not allow setting any of the StageProps. As defined here

aws-cdk/packages/@aws-cdk/core/lib/stage.ts

Lines 13 to 43 in 15cb919

	/**
	* Default AWS environment (account/region) for `Stack`s in this `Stage`.
	*
	* Stacks defined inside this `Stage` with either `region` or `account` missing
	* from its env will use the corresponding field given here.
	*
	* If either `region` or `account`is is not configured for `Stack` (either on
	* the `Stack` itself or on the containing `Stage`), the Stack will be
	* *environment-agnostic*.
	*
	* Environment-agnostic stacks can be deployed to any environment, may not be
	* able to take advantage of all features of the CDK. For example, they will
	* not be able to use environmental context lookups, will not automatically
	* translate Service Principals to the right format based on the environment's
	* AWS partition, and other such enhancements.
	*
	* @example
	*
	* // Use a concrete account and region to deploy this Stage to
	* new Stage(app, 'Stage1', {
	* env: { account: '123456789012', region: 'us-east-1' },
	* });
	*
	* // Use the CLI's current credentials to determine the target environment
	* new Stage(app, 'Stage2', {
	* env: { account: process.env.CDK_DEFAULT_ACCOUNT, region: process.env.CDK_DEFAULT_REGION },
	* });
	*
	* @default - The environments should be configured on the `Stack`s.
	*/
	readonly env?: Environment;

, env allows setting the region from which all other resources in the stage will use.

Even when casting as any to force env into Apps constructor, App ignores props as a whole and only passes outdir as can be seen here:

aws-cdk/packages/@aws-cdk/core/lib/app.ts

Lines 160 to 162 in 15cb919

	super(undefined as any, '', {
	outdir: props.outdir ?? process.env[cxapi.OUTDIR_ENV],
	});

Also of note, not passing a region to a Stack constructor's props will default the stack to us-east-1 even though --verbose output shows that CDK_DEFAULT_REGION has been correctly pulled from ~/.aws/config.

Expected Behavior

I would expect a number of things here:

1. We can set the region for the entire stage, via App in AppProps
2. The stage and stacks within it would use the value present in CDK_DEFAULT_REGION if nothing was specified manually in props
3. There would be a warning that CDK_DEFAULT_REGION diverged from what the default value of us-east-1 with instructions or hints as to how to proceed.

Current Behavior

The stage silently defaults to us-east-1

Reproduction Steps

Please reference code permalinks above

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.68.0

Framework Version

2.68.0

Node.js Version

18

OS

Mac Vetura

Language

Typescript

Language Version

4.9

Other information

No response

[pahud]

Thank you for the feedback. I will bring it up to the core team for further discussion.