Environment variable precedence

When working with environment variables in configuration management, ensure proper precedence handling and use clean fallback patterns. Environment variables can be inherited by subprocesses unexpectedly, potentially overriding command-line flags or other configuration sources.

Key practices:

1. Explicit precedence control: When spawning subprocesses, explicitly control which environment variables are passed to prevent unintended inheritance that could override intended configuration
2. Clean fallback patterns: Use utilities like cmp.Or() for cleaner environment variable fallback chains instead of verbose loops

Example of clean fallback pattern:

// Instead of verbose loops:
editor := "vi"
for _, v := range []string{"TELEPORT_EDITOR", "VISUAL", "EDITOR"} {
    if value := os.Getenv(v); value != "" {
        editor = value
        break
    }
}

// Use clean fallback:
editor := cmp.Or(os.Getenv("TELEPORT_EDITOR"), os.Getenv("VISUAL"), os.Getenv("EDITOR"), "vi")

This prevents configuration conflicts where subprocess environment variables might override parent process flags, and makes environment variable fallback logic more readable and maintainable.