What is a defect lifecycle?

The defect lifecycle (bug lifecycle) describes the states a defect goes through from discovery to closure. Typical states: New: defect reported for the first time. Assigned: assigned to a developer. Open: developer starts working on it. Fixed/Resolved: developer believes it's fixed. Ready for QA: ready for testing. Closed: QA verified the fix works. Reopened: fix didn't work, defect regressed, or invalid fix. Deferred: fix postponed to a later release. Rejected: not a real defect (works as designed, cannot reproduce). Additional states may include Duplicate (same issue reported before). Good defect reports include: title, environment, steps to reproduce, expected vs actual behavior, severity, priority, and screenshots/logs. Tools: Jira, GitHub Issues, Linear, Bugzilla. Priority (business impact) and severity (technical impact) are often different — a cosmetic bug on the homepage might be high priority but low severity.