Fixed: Describe Affected Now Detects Component File Changes

Atmos now correctly detects component file changes when running atmos describe affected. A regression introduced in v1.195.0 caused changes to Terraform, Helmfile, or Packer component files to not be detected when atmos.yaml was located in a subdirectory of the git repository (e.g., when using atmos -C path/to/project).

The Problem

When using atmos describe affected to identify components impacted by code changes, the command was only detecting stack configuration changes but missing actual component file changes. For example, modifying a main.tf file inside a Terraform component folder would not mark that component as affected.

This issue occurred because git diff returns file paths relative to the git repository root, while the path resolution was using the current working directory. This caused path mismatches in the following scenarios:

• Using -C flag: Running atmos -C path/to/project describe affected from a parent directory
• Subdirectory projects: When atmos.yaml is located in a subdirectory of the git repository
• Monorepo setups: When multiple Atmos projects share a single git repository

The Fix

We updated the changed files indexing logic to properly resolve relative paths against the git repository root instead of the current working directory. The fix ensures that:

• Relative paths from git diff are correctly resolved against the git repo root
• Component folder changes are detected regardless of where Atmos is executed from
• Individual file changes within component directories are properly tracked

Example

Now when you modify component files, atmos describe affected correctly identifies them:

# Modify a component file
echo "# comment" >> components/terraform/vpc/main.tf

# Run describe affected
atmos describe affected --ref refs/heads/main

# Output now includes the vpc component
[
  {
    "component": "vpc",
    "stack": "plat-ue2-dev",
    "affected": "component"
  }
]

Usage

Upgrade to the latest version of Atmos and run:

atmos describe affected --ref refs/heads/main

The command now correctly detects:

• Changes to component folders (Terraform, Helmfile, Packer)
• Changes to individual files within components
• Stack configuration changes (as before)
• Vendored components configured with source (even without an explicit component field)

This fix ensures your CI/CD pipelines accurately identify which components need to be deployed based on actual code changes.