(pipelines): v1 Cloud Assembly Schema version bumps break pipelines until v2 CDK CLI is released

[misterjoshua]

What is the problem?

v1.139.0 synthesizes Cloud Assembly Schema Version 16.0.0, but the latest CLI doesn't support it. In CDK Pipelines, without explicitly setting cliVersion: '1', the self-mutation step currently fails.

I'm sure that v2's CLI will be released soon, but given that the latest CLI may continue to be released out of step with (and later than) v1 schema version bumps, I wonder if many Pipelines users will get caught by this issue whenever v1 gets the schema bump first, like until the user sets cliVersion explicitly.

Reproduction Steps

https://cdk-dev.slack.com/archives/C018XT6REKT/p1641967038204400?thread_ts=1641940855.193800&cid=C018XT6REKT

What did you expect to happen?

Pipelines should use CDK CLI v1 to self-mutate.

What actually happened?

Pipelines used CDK CLI v2 (latest) which doesn't yet support the latest Cloud Assembly Schema Version, so it threw an error.

CDK CLI Version

2.5.0

Framework Version

1.139.0

Node.js Version

N/A

OS

Linux

Language

Typescript

Language Version

TypeScript (4.5.4)

Other information

Would it make the user's life easier if the Pipelines construct defaulted cliVersion to "1" rather than blank when synthesizing a v1 app? The changes would be here:

aws-cdk/packages/@aws-cdk/pipelines/lib/codepipeline/codepipeline.ts

Line 606 in e23b63f

const installSuffix = this.props.cliVersion ? `@${this.props.cliVersion}` : '';

aws-cdk/packages/@aws-cdk/pipelines/lib/codepipeline/codepipeline.ts

Line 652 in e23b63f

const installSuffix = this.props.cliVersion ? `@${this.props.cliVersion}` : '';

[polothy]

@rix0rrr and CDK team friends - it would be helpful to make it clear if CDK CLI v2 is supposed to work with CDK v1 Apps. When I read the "CDK Toolkit compatibility" section of the migration doc, I thought CDK CLI v2 could work with either v1 or v2 CDK apps (I could be totally wrong 😄). Thanks for your help on this! 🍻

[rix0rrr]

Yes, CLIv2 works with v1 apps. It's just that the way our release train works, the statement "the CLI must have equal version or higher" becomes a bit inscrutable.

This situation is an artifact of us still supporting (and developing on) v1 for the next 6 months. Once we drop support for v1, all future changes will go into v2 directly and any inconsistency windows will disappear.

[github-actions]

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