[pipelines] SimpleSynthAction with subdirectory prop specified produces a wrong buildspec

[tomas-mazak]

SimpleSynthAction uses path.join() function to render path to artifacts. It seems that buildspec requires the path to use forward-slash as a path separator (probably as the synth action runs on Linux), however, path.join() produces a path with backslashes when synthesis is run on Windows. This should hence be hardcoded to join by forward slash (/).

I believe the bug is here:

https://github.com/aws/aws-cdk/blob/master/packages/%40aws-cdk/pipelines/lib/synths/simple-synth-action.ts#L376

Reproduction Steps

Instantiate a CdkPipeline with following synthAction:

const synthAction = cdkpipelines.SimpleSynthAction.standardNpmSynth({
  sourceArtifact,
  cloudAssemblyArtifact,
  subdirectory: 'cdk',
});

Run cdk synth on Windows machine.

What did you expect to happen?

In synth action CodeBuild project's buildspec, the following should be present:

{
  "artifacts": {
    "base-directory": "cdk/cdk.out",
    "files": "**/*"
  }
}

What actually happened?

If synthetized on Windows machine, result is as follows:

{
  "artifacts": {
    "base-directory": "cdk\\cdk.out",
    "files": "**/*"
  }
}

This causes the artifact to be packaged incorrectly and the subsequent UpdatePipeline action fails as it cannot find the cloud assembly in the expected path.

Environment

• **CDK CLI Version : 1.73.0 (build eb6f3a9)
• **Framework Version : 1.72.0
• **Node.js Version : v10.16.3
• **OS : Windows 10 Enterprise 1909
• **Language (Version): Typescript 3.9.7

Other

I will raise a PR to fix this shortly.

---

This is 🐛 Bug Report

[hoegertn]

Shouldn't this be solved by the first mutation as the synth is running on Linux too in the CodePipeline synthesize step?

[tomas-mazak]

Shouldn't this be solved by the first mutation as the synth is running on Linux too in the CodePipeline synthesize step?

@hoegertn, That very first mutation fails already because of this bug:

Error: ENOENT: no such file or directory, open 'manifest.json'

[hoegertn]

Got it. Can you provide a PullRequest with a fix? Should be straight forward.

[github-actions]

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