Summary

This PR improves the status messages displayed during era file downloads to provide clearer feedback to users about the file state.

Problem

Previously, all era files would show the generic message "is stale" regardless of whether the file was missing or had a hash mismatch. This caused confusion for users who couldn't distinguish between different file states.

Solution

Modified the DownloadFile function in internal/download/download.go to:

• File not found: Display "not found, downloading..."
• Hash mismatch: Display "is stale (hash mismatch)"
• File up-to-date: Display "is up-to-date" (unchanged)

Changes

• Modified internal/download/download.go:

  • Enhanced error handling in DownloadFile function
  • Added distinction between os.IsNotExist and hash mismatch errors
  • Improved user feedback with specific status messages

• Added internal/download/download_test.go:

  • Comprehensive tests for all three file states
  • Tests for error type detection
  • Verification of correct download behavior

Testing

go test ./internal/download -v

All tests pass, covering:

• File not found scenario
• File exists with correct hash
• File exists with wrong hash
• Error type verification

Fixes

Closes #31917