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I was told that I can do `new StackReference` as many times I need, but when I put it in a function and it gets called twice, I get `resource 'urn:pulumi:app-staging::ckc-test::pulumi:pulumi:StackReference::seunggs/ckc-test/app-build' registered twice (read and read)` error and `pulumi up` fails during preview. What am I doing wrong?

it needs to have a unique name, can you share your code?

```const main = async () =&gt; {

    const stack = pulumi.getStack()

    const checkStackExists = (qualifiedStackName: string) =&gt; {
        try {
            const stackRef = new pulumi.StackReference(qualifiedStackName)
            return true
        } catch (err) {
            return false
        }
    }

    const checkAppBuildStackExists = () =&gt; {
        return checkStackExists(`${organization}/${project}/app-build`)
    }

    const getAppBuildStackOutputs = () =&gt; {
        const appBuildStackRef = new pulumi.StackReference(`${organization}/${project}/app-build`)
        const appEcrImageUrl = appBuildStackRef.getOutput('imageUrl') as pulumi.Output&lt;string&gt;
        return appEcrImageUrl
    }

    if (stack === 'app-staging' || stack === 'app-prod') {
        const appEcrImageUrl = checkAppBuildStackExists ? getAppBuildStackOutputs() : ''

        const { AppStack } = await import('./pulumi/stacks/app')
        const appStackOutput = new AppStack('app-stack', {
            imageUrl: appEcrImageUrl,
        }, { provider: k8sProvider })
        return appStackOutput
    }

}

export = main```

This is roughly the code - not sure what you mean by unique name? I thought you get stack reference by stack’s fully qualified name which is unique of course (i.e. no two stacks with the same name)

<@UCWG26BH7> still blocked by this - any idea why this is happening?

sory I'm at re:invent this week so slow to respond. It's working by design, you'll need to modify your code to only populate the stack ref once

Oh right - re:invent. No worries. So you CANNOT do `new StackReference` multiple times then?

So if this is the case, any way to check if the stack exists? The problem is I cannot call `new StackReference` freely because it errors out if the stack doesn’t exist.

You can do multiple StackReferences if you specify a unique identifier as a separate parameter. StackReference acts as a resource, so you can't declare it twice.

Here's an example in Python:
```stack = pulumi.StackReference("unique_id_1", stack_name="blabla")
same_stack_again = pulumi.StackReference("unique_id_2", stack_name="blabla")```

So I'm referencing the stack `blabla` twice. The other way of doing it is changing your code so that you only need to reference it once, but this give you options.