debuggingEASYDEBUGGING
Warm up with null path crash
Easy Debugging arena: stack traces, nullability, and guard placement
XP reward
90
Coins
8
Target time
12m
A profile page crashes only for users who have never uploaded an avatar. You are working inside a debugging war room, and the arena only clears when the result is safe, deterministic, and explainable.
Learning objective
Learn to apply stack traces, nullability, and guard placement in a debugging war room while explaining the invariant, safety constraints, and hidden edge cases.
Mission order
A stack trace points to avatar.url.split and test data omits avatar. Implement the direct solution first, then document the one edge case that can break it. Submit the solution plus enough reasoning to pass hidden edge cases.Visible checks
reproduces the reported failure
Expected: minimal failing case
adds a regression test
Expected: test fails before fix
Clear requirements
- Demonstrates stack traces, nullability, and guard placement
- Handles the visible sample and hidden edge cases
- Keeps output deterministic and explainable
- Avoids unsafe dynamic execution
Secure validation contract
Judge type
DEBUGGING
Complexity target
Minimal reproduction, source-cause fix, and regression test
Workspace
Code editor
typescriptsafe mock judge
Charging editor core
Test Results
Run the visible checks when your first pass is ready.
Clear Protocol
1Read the scenario and restate the expected output shape.
2Run visible checks before chasing hidden edge cases.
3Use Genie for one nudge if stuck, then explain the invariant.
4Submit only when the result is deterministic and safe.
Rewards
XP
90
Coins
8
Mission Route
Hints
Hints are metered and logged for No Hint Hero runs.
Genie Mentor Core
Hint protocol / contextual guardrails active
Progressive hints
Failed-test aware
Solution guarded
Mission: debugging-easy-null-path0 attempts0 failed tests0 hints used
Progressive hint depth
Genie: Genie online. I use your mission, attempts, failed tests, hints, and path context to coach the next rep without dumping answers first.