Peer dependencies are never direct

[mxdvl]

What does this change?

Make the following direct dependencies that are already listed as peers, dev: aws-cdk-lib, constructs. This matches the setup of aws-cdk.

How to test

Install the package somewhere.

How can we measure success?

Declaring peer dependencies that are also direct ones has no value

Have we considered potential risks?

Consumers should ensure that they have the correct peer dependencies

Checklist

• I have listed any breaking changes, along with a migration path ¹
• I have updated the documentation as required for the described changes ²

Footnotes

1. Consider whether this is something that will mean changes to projects that have already been migrated, or to the CDK CLI tool. If changes are required, consider adding a checklist here and/or linking to related PRs. ↩

2. If you are adding a new construct or pattern, has new documentation been added? If you are amending defaults or changing behaviour, are the existing docs still valid? ↩

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🦋 Changeset detected

Latest commit: ee87cff

The changes in this PR will be included in the next version bump.

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@guardian/cdk	Patch

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[akash1810]

Declaring peer dependencies that are also direct ones has no value

This package uses peerDependencies as a way to dictate which version of AWS CDK must be used by consumers of GuCDK.

If a different version of aws-cdk, aws-cdk-lib, or constructs is used, some fairly cryptic stack traces are seen¹, similar to:

    lib/my-app.test.ts:9:29 - error TS2345: Argument of type 'Stack' is not assignable to parameter of type 'Stack'.
      Type 'Stack' is missing the following properties from type 'Stack': _suppressTemplateIndentation, _terminationProtection, toYamlString

    9   expect(Template.fromStack(stack).toJSON()).toMatchSnapshot();

Use of peerDependencies produces a warning at installation time when mismatched versions of used. The idea is that message provides a way to triage the above issue.

If there's a better way describe this in the package.json that'd be amazing! I think the changes in this PR break the above description.

Footnotes

1. The are a few Chat threads sharing confusion on this stack trace. ↩

[mxdvl]

Declaring peer dependencies that are also direct ones has no value

This package uses peerDependencies as a way to dictate which version of AWS CDK must be used by consumers of GuCDK.

Yes, that’s a correct definition of what peer dependencies are meant to do. However, I’m not sure what specifying a dependency as both peer and direct achieves. It’s not a defined behaviour in the docs. Peer dependencies are automatically installed by NPM since v7, so there’s no need to specify it as a direct one to install it.

[akash1810]

If a different version of aws-cdk, aws-cdk-lib, or constructs is used, some fairly cryptic stack traces are seen

https://github.com/guardian/service-catalogue/pull/680/files for a real-life example (see the added annotations).

[akash1810]

Just to note this change follows the advice in https://docs.aws.amazon.com/cdk/v2/guide/manage-dependencies.html:

If you're developing a construct library, specify its dependencies via a combination of the peerDependencies and devDependencies sections