config-state-patterns

Prevent configuration file corruption during concurrent writes by applying lock-based access patterns and atomic file replacement, ensuring incomplete data is never persisted even if a crash occurs mid-write.

Merge configuration files with new defaults using a known-keys-only filtering approach, combining saved values with current defaults so older or incomplete files still work without losing existing settings.

Organize config, state, and secrets using conventional XDG-style storage layouts, placing host settings, session state, and auth tokens into predictable, separated, and protected file paths.

Atomic file replacement works for async or threaded state persistence by coordinating reads and writes with concurrency guardrails and locks, preventing race conditions and configuration drift.

Your application loses settings during configuration file changes because it lacks defaults merging and known-keys-only filtering, which prevents configuration drift by safely preserving valid older values.