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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Assigning hn.C after construction bypasses constants validation and fails far from the cause","articleBody":"#226 added validation of the `constants` argument in `HumanName.__init__`, but `C` is a plain attribute, so post-construction assignment bypasses it entirely:\n\n```python\nfrom nameparser import HumanName\n\nhn = HumanName('John Doe')\nhn.C = 'garbage'                    # accepted silently\nhn.full_name = 'Dr John Smith'\n# AttributeError: 'str' object has no attribute 'regexes'\n# — raised deep inside collapse_whitespace, no mention of C\n```\n\nThe error surfaces at the wrong layer with no pointer to the actual mistake.\n\nFix: make `C` a property whose setter reuses the constructor's check (extract a shared `_validate_constants` helper) so both assignment paths give the same immediate `TypeError`.\n\nRelated detail once this is fixed at the source: the pickle sentinel in `__getstate__`/`__setstate__` maps `C is CONSTANTS` to `None` and any `None` back to `CONSTANTS`, so an instance whose `C` was corrupted to `None` via this bypass currently round-trips to the shared singleton — silently \"healing\" the corruption and flipping `has_own_config`. A dedicated module-level sentinel object instead of `None` would remove that ambiguity; likely moot if the setter validation lands.\n\nFound by review of PR #237 — pre-existing, unrelated to that change.","author":{"url":"https://github.com/derek73","@type":"Person","name":"derek73"},"datePublished":"2026-07-06T00:49:30.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/239/python-nameparser/issues/239"}