Advanced Reproduction & Triage
Purpose: Advanced reproduction methods and formal severity / priority scoring. Read when: Reproduction is difficult, failures are flaky, or business prioritization needs formal scoring.
Contents
- Time-travel debugging
- Flaky-test strategy
- severity vs priority
RICE/ICE- Assess-phase template
Time-Travel Debugging
Use for heisenbugs, race conditions, or failures that disappear under observation.
| Tool | Target | Overhead | Strength |
|---|---|---|---|
rr |
Linux, C/C++/Rust | ~1.2x |
reverse execution, watchpoints |
| Replay.io | browser, JS/TS | ~3% |
deterministic browser replay |
| Pernosco | rr-based Linux analysis | cloud | collaborative analysis |
rr Flow
rr record ./program
rr replay
(rr) reverse-continue
(rr) reverse-step
(rr) watch -l varReplay.io Flow
- record the failing run
- upload the session
- inspect with DevTools without local reproduction
Flaky-Test Strategy
Common causes:
- shared test state
- fixed
sleep - random data
- current-time dependency
- unmanaged external dependencies
- race conditions
Management sequence:
Detect -> Quarantine -> Root Cause -> Fix -> Monitor
Severity Vs Priority
| Concept | Meaning | Evaluate By |
|---|---|---|
| Severity | how bad the bug is technically | data loss, feature failure, workaround availability |
| Priority | how soon to fix it | business impact, user count, SLA |
Extended severity classes:
| Level | Meaning | SLA Guide |
|---|---|---|
Blocker |
cannot continue using or testing the software | immediate |
Critical |
major function fully unusable | within 4 hours |
Major |
important function impaired, workaround exists | within 24 hours |
Minor |
limited user impact | next sprint |
Trivial |
no functional impact | backlog |
RICE And ICE
RICE
RICE Score = (Reach × Impact × Confidence) / Effort
| Factor | Scale |
|---|---|
| Reach | absolute count |
| Impact | 3, 2, 1, 0.5, 0.25 |
| Confidence | 100%, 80%, 50% |
| Effort | estimated person-months |
ICE
ICE Score = Impact × Confidence × Ease
| Factor | Scale |
|---|---|
| Impact | 1-10 |
| Confidence | 1-10 |
| Ease | 1-10 |
Selection Rule
| Situation | Prefer |
|---|---|
| data-rich prioritization | RICE |
| fast rough prioritization | ICE |
| user-count sensitivity matters | RICE |
| fix-cost comparison matters | RICE |
Assess-Phase Template
## Impact Assessment
### Severity: [Blocker|Critical|Major|Minor|Trivial]
### Priority: [P0|P1|P2|P3]
### Quantitative Impact
- Affected users: ___
- Affected transactions/day: ___
- Estimated revenue impact: ___
- SLA breach risk: [Yes/No]
### RICE Score
- Reach: ___
- Impact: ___
- Confidence: ___
- Effort: ___
- Score: ___
### Workaround
- Available: [Yes/No]
- Description: ___