fix: update default runtime to support CDK < 2.105.0

[blimmer]

As of version 3.x, this project now uses the Runtime.PROVIDED_AL2023 runtime. However, this enumerated value does not exist in older versions of aws-cdk, prior to [email protected]. If you use a version older than that, you get this cryptic error:

TypeError: Cannot read properties of undefined (reading 'name')
    at new Function (/home/runner/work/cdk-bug-reports/cdk-bug-reports/node_modules/aws-cdk-lib/aws-lambda/lib/function.js:1:11075)
    at SingletonFunction.ensureLambda (/home/runner/work/cdk-bug-reports/cdk-bug-reports/node_modules/aws-cdk-lib/aws-lambda/lib/singleton-lambda.js:1:2886)
    at new SingletonFunction (/home/runner/work/cdk-bug-reports/cdk-bug-reports/node_modules/aws-cdk-lib/aws-lambda/lib/singleton-lambda.js:1:866)
    at new ECRDeployment (/home/runner/work/cdk-bug-reports/cdk-bug-reports/node_modules/cdk-ecr-deployment/src/index.ts:140:20)
    at new TestCdkVersionStack (/home/runner/work/cdk-bug-reports/cdk-bug-reports/lib/test-cdk-version-stack.ts:9:5)
    at Object.<anonymous> (/home/runner/work/cdk-bug-reports/cdk-bug-reports/bin/test-cdk-version.ts:7:1)
    at Module._compile (node:internal/modules/cjs/loader:1376:14)
    at Module.m._compile (/home/runner/work/cdk-bug-reports/cdk-bug-reports/node_modules/ts-node/src/index.ts:1618:23)
    at Module._extensions..js (node:internal/modules/cjs/loader:1435:10)
    at Object.require.extensions.<computed> [as .ts] (/home/runner/work/cdk-bug-reports/cdk-bug-reports/node_modules/ts-node/src/index.ts:1621:12)

Therefore, we're not using the static version, instead new-ing it up: https://github.com/aws/aws-cdk/blob/b49032b3a6e549783b45492ffc76880fbcd58e68/packages/aws-cdk-lib/aws-lambda/lib/runtime.ts#L300-L303

[blimmer]

You shouldn't need to specify this. It's controlled by the upstream projen config and the peerDependencies it produces. In fact, this caused problems for me because yarn used a newer aws-cdk-lib version than what's specified in your peer deps.

[blimmer]

cc @SamStephens @fabiozig @scanlonp , who authored/approved #424

[blimmer]

Alternatively, you could new-up the Runtime yourself to have additional compatibility:

https://github.com/aws/aws-cdk/blob/169fd91e135556b8efb59d631acaf9a3426eaa53/packages/aws-cdk-lib/aws-lambda/lib/runtime.ts#L284-L287

It still probably makes sense to spot-check your code and have a more specific minimum version, still, though.

[fabiozig]

I also had the same problem and I had to change the version manually in my projects. I also agree with changing the dependency to peerDependencies, and devDependencies only. Even cdk documentation suggests this approach:

For projects that are CDK libraries in NPM, declare them both under the devDependencies and peerDependencies sections. To make sure your library is compatible with the widest range of CDK versions: pick the minimum aws-cdk-lib version that your library requires; declare a range dependency with a caret on that version in peerDependencies, and declare a point version dependency on that version in devDependencies.

https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib-readme.html

Could this be a breaking change in case the dependencies are removed?

[mrgrain]

I reckon we should keep everything else as it is and change the default to new Runtime('provided.al2023', RuntimeFamily.OTHER)

[blimmer]

Sounds good @mrgrain - I updated this PR as requested.