Defect Life Cycle: From Discovery to Closure

What is Defect Life Cycle?

The defect life cycle (bug life cycle) describes the journey of a defect from discovery through resolution and closure. Understanding this cycle ensures efficient bug tracking, clear communication, and timely resolution.

Effective defect management requires more than just tracking statuses. Writing bug reports that developers love accelerates the resolution process. Integrating defect tracking into continuous testing in DevOps provides visibility across the development pipeline. A solid test automation strategy helps prevent defects from reaching later stages of the lifecycle.

Defect Life Cycle Stages

1. New

Description: Defect reported by tester, not yet reviewed. Actions: Tester logs defect with details (steps, screenshots, severity).

2. Assigned

Description: Defect triaged and assigned to developer. Actions: Manager/Lead reviews, assigns to appropriate developer.

3. Open

Description: Developer begins investigating/fixing. Actions: Developer confirms defect, starts work.

4. Fixed

Description: Developer completes fix, ready for verification. Actions: Code changes implemented, pushed to test environment.

5. Retest

Description: Tester verifies fix. Actions: Tester executes test cases to confirm resolution.

6. Verified/Closed

Description: Fix confirmed, defect closed. Actions: Tester confirms resolution, updates status to closed.

Alternative Paths

Rejected

Description: Defect deemed invalid (not a bug, works as designed). Reason: Cannot reproduce, expected behavior, duplicate.

Deferred

Description: Valid defect postponed to future release. Reason: Low priority, not critical for current release.

Reopened

Description: Fix didn’t resolve issue or introduced regression. Actions: Tester reopens defect with details, reassigned to developer.

Defect Life Cycle Workflow

[New] → [Assigned] → [Open] → [Fixed] → [Retest] → [Verified] → [Closed]
   ↓         ↓          ↓         ↑                      ↓
[Rejected] [Deferred] [Reopened]──┘                 [Reopened]

Defect Attributes

Essential Fields

Field	Description	Example
ID	Unique identifier	BUG-1234
Title	Brief summary	“Login fails with valid credentials”
Description	Detailed explanation	Steps to reproduce, expected vs actual
Severity	Impact on system	Critical, High, Medium, Low
Priority	Urgency of fix	P1, P2, P3, P4
Status	Current state	New, Open, Fixed, Closed
Assigned To	Responsible developer	john.doe@company.com
Reporter	Who found it	qa.tester@company.com
Environment	Where found	Production, Staging, Dev
Version	Software version	v2.3.1
Attachments	Screenshots, logs	screenshot.png, error.log

Severity vs Priority

Severity	Priority	Example
Critical	P1	Payment processing broken - fix immediately
High	P1	User data exposed - security risk
Medium	P2	Search returns incorrect results
Low	P3	Cosmetic UI issue
Critical	P2	Rare edge case crash (affects < 1% users)
Low	P1	CEO demos tomorrow, cosmetic fix needed

Severity = Technical impact Priority = Business urgency

Best Practices

1. Write Clear Defect Reports

Bad Defect Report:

Title: Login doesn't work
Description: I tried to login and it failed.

Good Defect Report:

Title: Login fails with "Invalid credentials" error for valid users

Description:
When attempting to log in with valid credentials, the system returns
"Invalid credentials" error and does not authenticate the user.

Steps to Reproduce:
1. Navigate to https://app.example.com/login
2. Enter username: test@example.com
3. Enter password: ValidPass123!
4. Click "Login" button

Expected Result:
User is authenticated and redirected to dashboard.

Actual Result:
Error message "Invalid credentials" displayed.
Login fails despite correct credentials.

Environment:
- Browser: Chrome 118.0
- OS: Windows 11
- Server: Staging (v2.3.1)

Additional Info:
- Issue started after deployment on 2025-10-01
- Affects all test accounts
- Console shows 401 error from /api/auth/login
- Screenshot attached: login-error.png

2. Use Consistent Severity/Priority Definitions

Severity Levels:

Critical (S1): System crash, data loss, security breach
High (S2): Major feature broken, significant functionality impacted
Medium (S3): Feature partially working, workaround available
Low (S4): Minor issue, cosmetic, no functional impact

Priority Levels:

P1: Fix immediately (blocker)
P2: Fix in current sprint
P3: Fix in next sprint
P4: Fix when time permits (backlog)

3. Defect Triage Process

Daily Triage Meeting (15-30 min):

Review new defects
Validate reproducibility
Assign severity and priority
Assign to developer
Set target resolution date

Criteria for Prioritization:

Impact (how many users affected?)
Frequency (how often does it occur?)
Workaround (is there an alternative?)
Business criticality (does it block revenue?)

4. Track Defect Metrics

Metric	Description
Open Defects	Total unresolved bugs
Defect Age	Days since reported
Mean Time to Resolve	Average fix time
Reopened Rate	% of defects reopened
Defect Density	Bugs per feature/module

5. Root Cause Analysis

For critical/recurring defects, conduct RCA:

5 Whys Technique:

Defect: Payment processing fails

Why? API returns 500 error
Why? Database connection timeout
Why? Connection pool exhausted
Why? Connections not released after use
Why? Missing finally block in code

Root Cause: Code defect - missing connection cleanup
Fix: Add proper connection management
Prevention: Code review checklist updated

Common Pitfalls

❌ Vague descriptions: “It doesn’t work” - provide specific steps

❌ Missing reproducibility: Can’t reproduce = can’t fix

❌ Incorrect severity: “Typo in footer” marked as Critical

❌ Duplicate defects: Check existing bugs before reporting

❌ No regression testing: Fix verified but related features not tested

❌ Skipping verification: Assuming fix works without testing

Defect Management Tools

Popular bug tracking systems:

Jira: Enterprise standard, highly customizable
GitHub Issues: Integrated with code, simple workflow
Bugzilla: Open-source, feature-rich
Azure DevOps: Microsoft ecosystem, integrated ALM
Linear: Modern, fast, developer-focused

Conclusion

A well-defined defect life cycle ensures bugs are tracked systematically from discovery to closure. Clear processes, consistent communication, and disciplined follow-through result in faster resolution, better quality, and improved team collaboration.

Key Takeaways:

Standardize workflow: Define clear stages and transitions
Write detailed reports: Steps, screenshots, environment details
Distinguish severity vs priority: Technical impact vs business urgency
Triage regularly: Daily review of new defects
Track metrics: Monitor resolution time, defect density
Conduct RCA: Learn from critical defects to prevent recurrence

Implement a structured defect life cycle, and your team will resolve bugs faster, reduce misunderstandings, and deliver higher-quality software.