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Mohit Sharma

NOTES

Engineering notes

Things I had to understand properly before I could explain them. Written while the confusion was still fresh, which is the only time the explanation is any use.

2026

  • 2026.08.29

    The interface lied, so the catch never fired

    One missing file took the whole API down, past five correctly written try/catch blocks, because the driver could not fail where they were looking.

    4 minBackendFailure modes

  • 2026.08.28

    An idempotency key should remember successes, not failures

    Caching a 409 against an idempotency key turned a temporary refusal into a permanent one, and made the retry button a lie.

    4 minDistributed systemsAPI

  • 2026.07.25

    A check that cannot run has not passed

    A safety gate that silently narrows when its configuration is missing is worse than one that is absent, because it still reports a verdict.

    Hardening a safety-critical system5 minSystem designSafety critical

  • 2026.07.25

    Seven predicates for one question

    Four screens showed an aircraft's status and three of them were wrong. The fix was not to pick the best of the seven definitions.

    Hardening a safety-critical system5 minSystem designBackend

  • 2026.07.25

    The defect owns the finding

    A pilot who found a fault mid-inspection could abandon the checklist or lie. Fixing that meant resisting the obvious second blocker.

    Hardening a safety-critical system4 minSystem designBackend