Pulumi program hangs when resource transformation throws an exception

[Zaid-Ajaj]

What happened?

When using a ResourceTransformation as a stack option and that transform throws an exception, pulumi preview and pulumi up hang forever.

Expected Behavior

pulumi preview and pulumi up should not hang, instead, the transformation should catch errors and show them to users.

Steps to reproduce

The following C# Pulumi program demonstrates the problem:

using System.Threading.Tasks;
using Pulumi;
using Pulumi.Aws.S3;

class MyStack : Stack
{
    static StackOptions Options() => new StackOptions()
    {
        ResourceTransformations = { FailingTransform() } 
    };

    public MyStack() : base(Options())
    {
        var bucket = new Bucket("my-bucket");
    }

    static ResourceTransformation FailingTransform() 
    {
        return args => 
        {
            throw new System.Exception("Boom!");
            return null;
        };
    }
}


class Program
{
    static Task<int> Main() => Deployment.RunAsync<MyStack>();
}

Output of pulumi about

CLI          
Version      3.78.1
Go Version   go1.20.7
Go Compiler  gc

Plugins
NAME    VERSION
aws     6.0.2
dotnet  unknown

Host     
OS       darwin
Version  13.2.1
Arch     arm64

Additional context

No response

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