René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Add Constants.copy(); deprecate constants=None","articleBody":"## Summary\n\n`constants=None` means \"construct a fresh private `Constants()`\" — a sentinel that means the opposite of what `None` conventionally means (the default here is the *shared* config), documented under a \"Potential Gotcha\" heading. 1.4 ships the explicit vocabulary and the deprecation warning; removal is #261 (2.0).\n\n```python\nHumanName(name)                              # shared CONSTANTS (unchanged)\nHumanName(name, constants=Constants())       # private, library defaults\nHumanName(name, constants=CONSTANTS.copy())  # private, snapshot of current shared config\n```\n\n## The trap the sentinel can't express\n\n\"Give me a private config\" is ambiguous between *fresh library defaults* and *a private snapshot of the current shared config*. `None` silently picks the first: customize `CONSTANTS.titles`, later pass `None` for \"my own config\", and the customizations are gone with no error. An explicit `Constants` argument forces the caller to answer the question; the missing piece is a nice spelling for the snapshot answer — `copy.deepcopy(CONSTANTS)` works (reliably since the 1.3.0 pickle/deepcopy fixes, which is what makes this cheap now), but nobody discovers `deepcopy` for config.\n\n## Checklist\n\n- [ ] Add `Constants.copy()` — deepcopy-based detached copy; `_on_change` rewiring is already handled by the deepcopy machinery landed in 1.3.0\n- [ ] `DeprecationWarning` when `constants=None` is passed explicitly, naming both replacements. Only *explicit* `None` warns — the signature default is `CONSTANTS`, so omitting the argument never hits the branch\n- [ ] Update the signature annotation in the same PR (`Constants | None` stays for 1.4, docstring marks `None` deprecated)\n- [ ] Docs in the same PR: the three-spelling vocabulary in customize.rst and a sentence on the defaults-vs-snapshot distinction\n","author":{"url":"https://github.com/derek73","@type":"Person","name":"derek73"},"datePublished":"2026-07-06T08:14:02.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/260/python-nameparser/issues/260"}