noteflow/.claude/hookify.block-datetime-now-fallback.local.md

name, enabled, event, pattern, action

name	enabled	event	pattern	action
block-datetime-now-fallback	true	file	return\s+datetime.now\s*(	block

BLOCKED: datetime.now() fallback detected

Returning datetime.now() as a fallback on parse failures causes data corruption.

Why this is dangerous:

• Silent data corruption - timestamps become incorrect without any error signal
• Debugging nightmare - no way to trace back to the original parse failure
• Data integrity loss - downstream consumers receive fabricated timestamps

What to do instead:

1. Return None and let callers handle missing timestamps explicitly
2. Raise a typed error (e.g., DateParseError) so failures are visible
3. Use Result[datetime, ParseError] pattern for explicit error handling

Examples from swallowed.md:

• _parse_google_datetime returns datetime.now(UTC) on ValueError
• parse_outlook_datetime returns datetime.now(UTC) on ValueError

Resolution pattern:

# BAD: Silent data corruption
except ValueError:
    logger.warning("Failed to parse: %s", dt_str)
    return datetime.now(UTC)  # Data corruption!

# GOOD: Explicit failure
except ValueError as e:
    raise DateParseError(f"Invalid datetime: {dt_str}") from e

# GOOD: Optional return
except ValueError:
    logger.warning("Failed to parse: %s", dt_str)
    return None  # Caller handles missing timestamp