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This atlas maps common misunderstandings to exact correction drills.
- "If code runs once, it is correct."
- "Passing one test means production-ready."
- "SQL reruns are safe by default."
- "Logging is optional for small tools."
- "Security can be added at the end."
- Symptom: what failure behavior appears.
- Root cause: what concept is misunderstood.
- Drill: one small exercise to prove the correction.
- Verification: one test or output expectation.
- Symptom: duplicated rows after ETL rerun.
- Root cause: missing idempotency key/upsert logic.
- Drill: run same batch twice and compare row counts.
- Verification: row count unchanged on second run.
- Symptom: random guessing during bug fixes.
- Root cause: no traceback reading habit.
- Drill: break one test intentionally and identify first failing line.
- Verification: fix targets root cause, not symptom.
- Pick one misconception category.
- Run one break/fix drill focused on that category.
- Capture before/after understanding note.