Defect Life Cycle: Complete Explanation with Examples

The Defect Life Cycle (also called Bug Life Cycle) describes the journey of a defect from discovery to resolution. It’s a critical process in software testing that ensures all issues are properly tracked, fixed, and verified.

1. What is Defect Life Cycle?

A structured process that:

• Tracks a defect through various stages
• Defines who is responsible at each stage
• Ensures proper documentation and resolution
• Provides metrics for quality improvement

Analogy:
Like a hospital patient’s journey: Admission → Diagnosis → Treatment → Recovery → Discharge

2. Defect Life Cycle States (Complete Flowchart)

[NEW] → [ASSIGNED] → [OPEN] → [FIXED] → [RETEST] → [VERIFIED] → [CLOSED]
    ↘       ↗             ↘             ↗
   [REJECTED]          [REOPENED]

3. Detailed Stages Explanation

1. New

• Description: When a tester first logs the defect
• Responsible: QA Engineer/Tester
• Documentation: Bug report with:
• Steps to reproduce
• Screenshots/videos
• Environment details
• Severity/Priority

Example:
Tester finds Myntra’s “Apply Coupon” button fails on iOS – logs new defect in JIRA

2. Assigned

• Description: Defect assigned to development team
• Responsible: Test Lead/Project Manager
• Documentation: Assignment details in tracking tool

Example:
Defect assigned to “Mobile Dev Team” with due date

3. Open

• Description: Developer starts analyzing/fixing
• Responsible: Developer
• Documentation: Technical analysis notes

Example:
Dev finds iOS Safari has caching issue with coupon API

4. Fixed

• Description: Developer resolves and marks as fixed
• Responsible: Developer
• Documentation: Code changes, fix version

Example:
Dev pushes fix to version 2.1.5 and updates ticket

5. Retest

• Description: QA verifies the fix
• Responsible: QA Engineer
• Documentation: Retest results

Example:
Tester verifies coupon works on iOS Safari 15+

6. Verified

• Description: Fix confirmed working
• Responsible: QA Lead
• Documentation: Verification sign-off

Example:
Test lead approves the fix after regression testing

7. Closed

• Description: Defect officially resolved
• Responsible: QA Lead/PM
• Documentation: Closure notes

Example:
Ticket closed after successful production deployment

4. Alternative Paths

A. Rejected

• When: If defect is invalid (duplicate, not a bug, can’t reproduce)
• Responsible: Developer/Test Lead
• Example:
  “Coupon error” was actually expired coupon – defect rejected

B. Reopened

• When: Fix doesn’t work during retest
• Responsible: QA Engineer
• Example:
  Coupon works but now causes cart calculation error – reopened

C. Deferred

• When: Postponed to future release
• Responsible: Product Manager
• Example:
  iOS 14 bug deferred as users are upgrading to iOS 15

5. Key Roles & Responsibilities

6. Essential Documents in Defect Life Cycle

1. Defect Report (Initial logging)

• Defect ID, Description
• Steps to reproduce
• Expected vs Actual results
• Environment details

1. Defect Log (Tracking)

• Status changes
• Assignee history
• Time tracking

1. Retest Report (Verification)

• Retest results
• Screenshots of fix
• Regression impact

7. Real-World Example (Myntra Case Study)

Scenario: “Sort by Price High-to-Low” shows incorrect order

1. New: Tester logs defect with example products
2. Assigned: To backend dev team
3. Open: Dev finds MongoDB sort query issue
4. Fixed: Corrects aggregation pipeline
5. Retest: QA verifies with 50 test products
6. Verified: All price sorts correctly
7. Closed: After production deployment

8. Best Practices

Clear Reproduction Steps – “How to reproduce” should be foolproof
Proper Severity/Priority – Critical vs Major vs Minor
Attach Evidence – Screenshots, logs, videos
Track Dependencies – Link related defects
Regular Triage Meetings – Discuss critical defects

9. Common Mistakes

Vague defect descriptions (“Not working”)
Not assigning proper severity
Skipping retest verification
Poor defect tracking (lost in emails/chats)
Closing without proper sign-off

10. Defect Metrics for Analysis

• Defect Density: Bugs per lines of code
• Defect Age: Time from New to Closed
• Rejection Rate: % of invalid defects
• Reopen Rate: % of defects reopened

Example Report:
“Mobile team reduced reopen rate from 15% → 5% after implementing better unit tests”

Conclusion

The Defect Life Cycle is the backbone of effective quality control. By rigorously following this process:

• Teams ensure no defects fall through cracks
• Developers get clear bug reports
• Managers gain visibility into quality
• Organizations improve product reliability

Final Tip:
“Treat every defect like a crime scene – document thoroughly, analyze carefully, and prevent recurrence!”