digraph assertion_vs_error {
    rankdir=TB;

    START [label="Handling a potentially\nbad condition" shape=doublecircle];
    never [label="Should this NEVER happen?\n(programmer bug)" shape=diamond];
    assertion [label="Use ASSERTION" shape=box style=filled fillcolor=lightblue];
    anticipated [label="Is it anticipated\nbad input?" shape=diamond];
    errorhandling [label="Use ERROR HANDLING" shape=box style=filled fillcolor=lightgreen];
    robust [label="Building highly\nrobust system?" shape=diamond];
    both [label="Use BOTH\n(assert + handle)" shape=box style=filled fillcolor=lightyellow];
    reconsider [label="Clarify requirements:\nIs it a bug or expected?\nAsk domain expert." shape=box style=filled fillcolor=lightcoral];

    START -> never;
    never -> robust [label="yes"];
    never -> anticipated [label="no"];
    robust -> both [label="yes"];
    robust -> assertion [label="no"];
    anticipated -> errorhandling [label="yes"];
    anticipated -> reconsider [label="no/unsure"];
}

digraph correctness_vs_robustness {
    rankdir=TB;

    START [label="Choose error\nhandling philosophy" shape=doublecircle];
    safety [label="Safety-critical?\n(medical, aviation, nuclear)" shape=diamond];
    correctness [label="Favor CORRECTNESS\nShut down > wrong result" shape=box style=filled fillcolor=lightcoral];
    consumer [label="Consumer app?\n(games, word processors)" shape=diamond];
    robustness [label="Favor ROBUSTNESS\nKeep running > perfect" shape=box style=filled fillcolor=lightgreen];
    analyze [label="ANALYZE DOMAIN\n(see guidance below)" shape=box style=filled fillcolor=lightyellow];

    START -> safety;
    safety -> correctness [label="yes"];
    safety -> consumer [label="no"];
    consumer -> robustness [label="yes"];
    consumer -> analyze [label="no"];
}

digraph debug_code_production {
    rankdir=TB;

    START [label="Should this debug\ncode stay in production?" shape=doublecircle];
    important [label="Checks important errors?\n(calculations, data integrity)" shape=diamond];
    keep1 [label="KEEP" shape=box style=filled fillcolor=lightgreen];
    crash [label="Causes hard crash?\n(no save opportunity)" shape=diamond];
    remove1 [label="REMOVE" shape=box style=filled fillcolor=lightcoral];
    diagnose [label="Helps remote diagnosis?\n(logging, state dumps)" shape=diamond];
    keep2 [label="KEEP as silent log" shape=box style=filled fillcolor=lightgreen];
    remove2 [label="REMOVE or make\nunobtrusive" shape=box style=filled fillcolor=lightyellow];

    START -> important;
    important -> keep1 [label="yes"];
    important -> crash [label="no"];
    crash -> remove1 [label="yes"];
    crash -> diagnose [label="no"];
    diagnose -> keep2 [label="yes"];
    diagnose -> remove2 [label="no"];
}

// BAD: Unhandled rejection crashes Node.js
async function fetchUser(id) {
  const response = await fetch(`/api/users/${id}`); // Can reject
  return response.json();
}

// GOOD: Explicit error handling
async function fetchUser(id) {
  try {
    const response = await fetch(`/api/users/${id}`);
    if (!response.ok) {
      throw new UserNotFoundError(id); // Domain-level exception
    }
    return response.json();
  } catch (e) {
    if (e instanceof UserNotFoundError) throw e;
    throw new UserServiceError('Failed to fetch user', { cause: e });
  }
}

// BAD: First rejection loses other results
const results = await Promise.all(promises);

// GOOD: Collect all results including failures
const results = await Promise.allSettled(promises);
const failures = results.filter(r => r.status === 'rejected');
if (failures.length > 0) {
  logErrors(failures);
  // Decide: fail entirely or continue with partial results?
}