Local Preview Should Support Symlinks or Explicitly Allow Them

Thank you for this feature request, Marty. We understand the friction you're experiencing when developing interdependent Terraform modules locally. After careful analysis, we've decided not to implement symlink support in local preview. Here's why:

Security & Determinism Concerns:

• Following symlinks could potentially expose files outside your project directory, creating security vulnerabilities

• Symlinks create non-deterministic behavior - what works on your machine may not work for teammates or in CI/CD

• Most importantly, local preview is designed to accurately simulate what will happen when you push to Spacelift. Since symlinked local files won't exist in our execution environment, supporting them would create false confidence

Recommended Solution: Terraform Override Files

Terraform has a built-in mechanism designed exactly for this use case - override files. Here's how to use them:

1. Create an override.tf file in your working directory:

# override.tf - for local development only
module "my_module" {
  source = "../path/to/local/module"
}

2. Add override.tf to your .gitignore to prevent committing local-only configuration

3. Run spacelift local-preview normally - it will use your local module source

4. When done with local development, simply delete the override.tf file

Example workflow:

# Start local development
echo 'module "my_module" { source = "../modules/my-module" }' > override.tf

# Test with local preview
spacelift local-preview

# Clean up when done
rm override.tf

This approach:

• Works today without any changes needed

• Uses Terraform's native functionality

• Maintains clear separation between local development and production configuration

• Ensures your local preview accurately represents what will run in Spacelift

We believe this pattern provides the rapid iteration you need while maintaining the security and reliability that Spacelift promises. Would this workflow address your local development needs?