Multistack-cross-stack-refference-error: bug?

[Dill-Dall]

Expected Behavior

I expect stack A to be independant of stack B since no dependencies are defined.

Actual Behavior

When using multistacks. I get an error on cross-referencing. Where the top stack is apparently dependent on the second stack, even when it should not be.

update:

Both the stacks sets up their own External Provider which used External Data. This is what caused the issue. Don't know if it's expected behaviour, though.
See comment.

const app = new App();
new app(app, "app-dev", devConfig);
new apiStack(app, "app-api-dev", devApiConfig);

app.synth();

[2024-02-24T02:06:22.792] [ERROR] default - ╷
│ Error: Unable to find remote state
│
│   with data.terraform_remote_state.cross-stack-reference-input-app-api-dev,
│   on cdk.tf.json line 64, in data.terraform_remote_state.cross-stack-reference-input-app-api-dev:
│   64:         "workspace": "${terraform.workspace}"
│
│ No stored state was found for the given workspace in the given backend.
app-dev  ╷
                 │ Error: Unable to find remote state
                 │
                 │   with data.terraform_remote_state.cross-stack-reference-input-app-api-dev,
                 │   on cdk.tf.json line 64, in data.terraform_remote_state.cross-stack-reference-input-app-api-dev:
                 │   64:         "workspace": "${terraform.workspace}"
                 │
                 │ No stored state was found for the given workspace in the given backend.

Steps to Reproduce

1. create two stacks - with their own state keys.

const app = new App();
new cargostream(app, "app-dev", devConfig);
new apiStack(app, "app-api-dev", devApiConfig);

app.synth();

2. Run cdktf plan "app-dev" - gives the unable to find remote state error.

3. Run cdktf plan "app-api-dev" No error

Versions

language: typescript
cdktf-cli: 0.20.3
node: v20.11.0
cdktf: 0.20.2
constructs: 10.3.0
jsii: null
terraform: 1.7.2
arch: arm64
os: darwin 22.5.0
providers
external@~>2.3.2 (LOCAL)
terraform provider version: 2.3.3
@cdktf/provider-aws (PREBUILT)
terraform provider version: 5.33.0
prebuilt provider version: 19.2.0
cdktf version: ^0.20.0

Providers

┌───────────────┬──────────────────┬─────────┬────────────┬─────────────────────┬─────────────────┐
│ Provider Name │ Provider Version │ CDKTF │ Constraint │ Package Name │ Package Version │
├───────────────┼──────────────────┼─────────┼────────────┼─────────────────────┼─────────────────┤
│ external │ 2.3.3 │ │ ~>2.3.2 │ │ │
├───────────────┼──────────────────┼─────────┼────────────┼─────────────────────┼─────────────────┤
│ aws │ 5.33.0 │ ^0.20.0 │ │ @cdktf/provider-aws │ 19.2.0 │
└───────────────┴──────────────────┴─────────┴────────────┴─────────────────────┴─────────────────┘

Gist

https://gist.github.com/Dill-Dall/f8214e40fc6bba1fe71763d804d6a2e3

Possible Solutions

No response

Workarounds

Removed the External providers (the outputs were cross reffed it seems. See comment)

Anything Else?

First timer on the repo.

References

https://discuss.hashicorp.com/t/cdk-multistacking-workspace-cross-reff-error/63108

Help Wanted

• I'm interested in contributing a fix myself

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[Dill-Dall]

Update:
I found the culprit, it was my use of the ExternalProvider in the stacks. But don’t understand why. The outputs of the external provider created the issue.

export function setupProvidersAndStateBackend(scope: Construct, envConfig: EnvConfig, tags: Tags): [AwsProvider, ExternalProvider] {
    validateEnvConfig(envConfig);

    const externalProvider = new ExternalProvider(scope, "external", {});

        const terraformVersion = new DataExternal(scope, "terraform_version", {
            program: ["bash", "-c", "echo '{\"version\": \"\'$(terraform version | grep 'Terraform v' | cut -d ' ' -f 2)\'\"}'"],
        });
        const cdktfVersion = new DataExternal(scope, "cdktf_version", {
            program: ["bash", "-c", "echo '{\"version\": \"\'$(cdktf --version)\'\"}'"],
        });

        tags.terraform_version = terraformVersion.result.lookup("version") as string;
        tags.cdkf_version = cdktfVersion.result.lookup("version") as string;

    ....

[DanielMSchmidt]

In general this should / can only happen if a token created in one stack is being used in another one. The example is too small / not complete enough to understand where the issue is coming from. There must be an implicit dependency between the two where e.g. the result from this function is used in both or sth similar. It would be helpful if you could share a complete example (ideally a minimal one).

[Dill-Dall]

thx for the feedback. I found the issue, all on my end. The reason was because I changed the "tags" constant. Meaning it made a cross stack reff for when multiple stacks used the same "tags" const.
Fixed it by creating a copy instead.

export function setupProvidersAndStateBackend(scope: Construct, envConfig: EnvConfig, tags: Tags, alignWithLegacy: boolean = false): ProviderStateConfig {
    validateEnvConfig(envConfig);

    const configGeneratedTags: { [key: string]: any } = {};

    const externalProvider = new ExternalProvider(scope, "external", {});
    if (alignWithLegacy == false) {


        const terraformVersion = new DataExternal(scope, "terraform_version", {
            program: ["bash", "-c", "echo '{\"version\": \"\'$(terraform version | grep 'Terraform v' | cut -d ' ' -f 2)\'\"}'"],

        });
        const cdktfVersion = new DataExternal(scope, "cdktf_version", {
            program: ["bash", "-c", "echo '{\"version\": \"\'$(cdktf --version)\'\"}'"],
        });

        configGeneratedTags['terraform_version'] = terraformVersion.result.lookup("version");
        configGeneratedTags['cdktf_version'] = cdktfVersion.result.lookup("version");

    }

    const awsProvider = new AwsProvider(scope, "AWS", {
        region: envConfig.region || "eu-north-1",
        defaultTags: [
            {
                tags: {
                    ...tags,
                    ...configGeneratedTags,
                    realm: envConfig.env,
                },
            },
        ],
....

[Dill-Dall]

My own bad code, not a bug 👍

[github-actions]

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